EP4688797A2

EP4688797A2 - Supramolecular hydroformylation catalyst

Info

Publication number: EP4688797A2
Application number: EP24715729.0A
Authority: EP
Inventors: Anton VIDAL FERRAN; Andrés ROMERO NAVARRO
Original assignee: Universitat de Barcelona UB; Institut Catala dInvestigacio Quimica ICIQ; Institucio Catalana de Recerca i Estudis Avancats ICREA
Current assignee: Universitat de Barcelona UB; Institut Catala dInvestigacio Quimica ICIQ; Institucio Catalana de Recerca i Estudis Avancats ICREA
Priority date: 2023-03-30
Filing date: 2024-03-22
Publication date: 2026-02-11
Also published as: WO2024200242A3; WO2024200242A2

Abstract

The invention refers to a hydroformylation catalyst of formula (I), which comprises a rhodium complex. It also refers to a process for preparing the catalyst, and to the use of the catalyst in hydroformylation reactions which show higher regioselectivity in favor or linear aldehydes, as well as higher conversion yields. It also refers to a ligand and a process for preparing the ligand.It refers also to a process for preparing aldehydes by a hydroformylation reaction.

Description

Supramolecular hydroformylation catalyst

TECHNICAL FIELD

The present invention relates to the field of catalysts used in hydroformylation reactions.

BACKGROUND ART

The hydroformylation reaction, also known as oxo process, is an industrial process for the production of aldehydes from alkenes.lt consists in the addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon double bond. This reaction is important because aldehydes may be converted into secondary products in an easy way.

This process is usually carried out with high pressures (between 10 and 100 atmospheres) of carbon monoxide and hydrogen, at temperatures between 40 °C and 200 °C, in the presence of transition metal catalysts.

Cobalt catalysts are used in the industrial processes known as BASF-oxo process, Exxon process, and Shell process, whereas rhodium catalysts are used in Union Carbide process, and Ruhrchemie/Rhone-Poulenc process.

The addition of CO and hydrogen to the double bond can afford two isomeric products: linear and branched:

CO/H₂

R-CH=CH₂ - ► R-CH₂-CH₂-CHO + R-CH-CH3

CHO linear branched

Since both products are not equally desirable, much request has been dedicated to the design of catalysts favoring one isomer or the other, depending on the needs.

In US4769498 it is disclosed a process for preparing aldehydes using metal- polyphosphite ligand complex compositions, which givesmixtures of linearbranched ratios and it is operated under mild conditions. The examples show that regioselectivity of the catalyst system is strongly dependent on the olefinic substrate.

Rhodium catalysts providing preferably linear aldehydes are disclosed in, for example, Cuny et al., Practical high yield, regioselective, rhodium-catalyzed hydroformylation of functionalized a-olefins, J. Am. Chem. Soc., 1993, 115, 2066-2058; van Rooy et al., Bulky diphosphite-modified rhodium catalysts: hydroformylation and characterization, Organometallics, 1996, 15, 835-847; Breit et al., Hydrogen bonding as a construction element for bidentate donor ligands in homogeneous catalysis: regioselective hydroformylation of terminal alkenes, J. Am. Chem. Soc., 2003, 125, 6608-6609; Breit et al., Self-assembly of bidentate ligands for combinatorial homogeneous catalysis based on an A-T base-pair model, Angew. Chem. Int. Ed., 2005, 44, 1640-1643; and Dydio et al., Precise supramolecular control of selectivity in the Rh-catalyzed hydroformylation of terminal and internal alkenes, J. Am. Chem. Soc., 2013, 135, 10817-10828.

In Linnebank et al., Regioselective hydroformylation of internal and terminal alkenes via remote supramolecular control, Chem. Eur. J., 2020, 26, 8214-8219, it is disclosed the redesign of a supramolecular Rh-bisphosphite hydroformylation catalyst containing a neutral carboxylate receptor, 7,7’-diamido-2,2’-diindolylmethane (DIM pocket), with a larger distance between the phosphite metal binding moieties and the DIM pocket, for obtaining a regioselective conversion of internal and terminal alkenes containing a remote carboxylate directing group.

In Mon et al., Bis(phosphite) ligands with distal regulation: application in rhodium- mediated asymmetric hydroformylations, Chem. Eur. J., 2013, 19, 2720-2725, it is disclosed that small amounts of achiral polyether binders are employed to enhance the enantioselectivity of the hydroformylation of diversely substituted substrates mediated by chiral rhodium complexes derived from the a,w-bis(phosphite)-polyether ligands. In the examples, it is shown a predominance of the branched aldehyde in front of the linear (terminal) aldehyde.

In Vidal-Ferran et al., Supramolecularly regulated ligands for asymmetric hydroformylations and hydrogenations, Chem. Eur. J., 2015, 21 , 11417-11426, it is disclosed the use of polyether binders as regulation agents to enhance the enantioselectivity of rhodium-catalyzed transformations. In the examples, it is disclosed that the branched aldehyde is the major product over the linear aldehyde.

In Rovira et al., Asymmetric hydroformylation of heterocyclic olefins mediated by supramolecularly regulated rhodium-bisphosphite complexes, J. Org. Chem., 2015, 80, 10397-10403, it is disclosed that rhodium complexes derived from conformationally transformable a,w-bisphosphite ligands combined with a suitable alkali metal [B(3,5- (CF₃)₂C6H₃)₄] (BArF ) salt as a regulation agentprovide high regio- and enantio- selectivities in the asymmetric hydroformylation of three heterocyclic olefins. In the examples, it is shown a predominance of the branched aldehyde in front of the linear (terminal) aldehyde.

Thus, in spite of the different hydroformylation catalysts disclosed in the prior art, there is a need for further hydroformylation catalysts showing higher regioselectivity in favor of linear aldehydes, in combination with higher conversion yields.

SUMMARY OF INVENTION

An aspect of the present invention relates to a hydroformylation catalyst. Another aspect of the invention relates to a ligand.

Another aspect of the invention relates to a process for preparing the ligand.

Another aspect of the invention relates to a process for preparing the catalyst.

Another aspect of the invention relates tothe use of thecatalyst in a hydroformylation reaction.

Another aspect of the invention is a process for preparing aldehydes by a hydroformylation reaction.

The present invention relates to a hydroformylation catalystof formula (I) comprising a rhodium carbonyl hydride [Rh], a ligand L and, optionally, a regulation agent [RA], wherein

[Rh] is Rh(CO)_x(H), wherein x is 1 or 2, preferably x is 2;

[RA] is a regulation agent selected from a salt of formula M⁺A , wherein M⁺ is selected from an alkali metal cation and ammonium, and A is a non-coordinating anion; the ligand Lhas formula (II)

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-P^erfl^uorc>alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected fromlinear or branched C1-C5 alkyl, linear or branched O-(Ci-C₅)- alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, and substituted or unsubstituted phenyl; more preferably beingt-Bu;

0 < m < 5;0 < n < 5; n+m > 1 ; p, q, r and s are independently selected from land 2; t is selected from 0 and 1 ; and u and v are independently selected from 1 , 2, 3 and 4.

The inventors of the present invention have developed new hydroformylation catalysts, which surprisingly show regioselective activity yielding selective formation of terminal aldehydes in front of branched aldehydes in combination with high conversion yields. The combination of a regulation agent, when t=1 , with a metal precursor with conformationally transformable ligands, which incorporate a polyether chain as the regulation site, behave as supramolecularly regulated catalysts. The regioselectivity in the hydroformylation may be maximized by the absence, when t=0, or the presence, when t=1 , of a specific regulation agent (RA). Said catalysts are assembled by means of multiple weak intramolecular interactions to perform supramolecular catalysis.

In an embodiment, supramolecular regulation of the catalytic site is a useful approach in catalysis. Said regulation refers to the addition of a chemical species, referred to as regulation agent (RA), when t=1 , that is not directly involved in the catalytic site but interacts with the assembled ligand (or catalytic system) through reversible interactions providing a change in the geometry of the catalytic site with respect to that obtained with other regulation agents. This strategy seeks to override one of the intrinsic limitations of catalysts: their lack of generality. It is well known in the field that structural changes in the substrate(s) often translate into a loss of selectivity, with structural variation of the catalytic system being required for improving the outcome of the reaction for the new substrate. Supramolecular regulation is an efficient strategy to produce libraries of catalysts, whose members preserve the main structural characteristics of the whole set of catalysts, but incorporate subtle structural differences at the catalytic site that are related to the regulation agent used. Overall, one of the members a particular library of catalysts is capable of adapting to the requirements of a given substrate, providing the highest performance in terms of regioselectivity for this particular substrate. Adapting the covalent backbone of a catalyst to increase their substrate scope faces significant synthetic hurdles.

In the present description, as well as in the claims, the singular forms "a", "an" and "the" include the plural reference unless the context clearly indicates otherwise. The term "about" refers to a deviation of plus/minus 10%, preferably plus/minus 5%. The percentages are expressed in % by weight (wt%), unless stated the contrary. The ranges defined by the terms "between ... and ..." or by the terms “from ... to... ” are meant to include also said stated endpoints thereof, and they also include any narrower sub-range.

Hydroformylation catalyst

The hydroformylation catalyst of the present invention comprises three differentiated parts: a rhodium carbonyl hydride[Rh], a ligand, and optionally a regulation agent [RA], In the case, t=1 , the equivalent ratio of [Rh]:[RA]:ligand is usually comprised between 1 :1 :1 and 1 :2: 1.2, preferably between 1 : 1.1 :1 and 1 :1.4: 1.1 , and more preferably between 1 :1.25:1.1 and 1 :1.35:1.1.

Rhodium carbonyl hydride [Rh]

In the context of the present invention [Rh] representsthe complex Rh(CO)_x(H), whereinx is 1 or 2, and preferably x is 2.

Regulation agent [RA]

The regulation agent is an optional feature of the catalyst, when t=0, RA is not present in the catalyst, and when t=1 it is present. In a preferred embodiment t=1.

[RA] is a regulation agent selected a salt of formula M⁺A , wherein M⁺ is selected from an alkali metal cation and ammonium, and A is a non-coordinating anion; preferably M⁺is an alkali metal cation, and yet more preferably M⁺ is selected from Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺. The non-coordinating anion A is preferably selected from BF₄ , PF₆ , CF₃COO or [B(3,5-(CF₃)₂C₆H₃)₄] (abbreviated as BArF), and more preferably is[B(3,5-(CF₃)₂C₆H₃)₄] (BArF).

The absence of the regulation agent or the presence of a specific regulation agent allows the modulation of the regioselectivity of the hydroformylation reaction as shown in the examples. Ligands

Another aspect of the invention is a ligand that is comprised in the structure of the hydroformylation catalyst of the invention, defined according to general formula (II) above.

In a preferred embodiment, R¹ = R⁴ and R² = R³.

In an embodiment, the ligand is according to general formula (II), wherein R¹, R², R³ and R⁴ are t-Bu, and p, q, r and s are 2, and R¹, R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings, 0 < m < 5 and 0 < n < 5 and n+m > 1 , and , , the meaning as above, in a preferred embodiment u and v are 0.

In an embodiment, the ligand is according to general formula (II), wherein R¹, R², R³ and R⁴ are t-Bu, and p, q, r and s are 2, and R¹, R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings, 0 < m < 5 and 0 < n < 5 and n+m > 1 , and X is oxygen. Thus, n+m is selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10; in a preferred embodiment n+m is an integer from 2to 5. In a preferred embodiment n+m is 2, in another preferred embodiment n+m is 5. For example, when n+m is 2, the ligand is defined according to formula (Ila):

For example, when n+m is 5, the ligand is defined according to formula (lib): In an embodiment, the ligand is according to general formula (II), wherein R¹, R², R³ and R⁴ are t-Bu, and p, g, r and s are 2, and R¹, R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings, 0 < m < 5 and 0 < n < 5 and n+m > 1 , and wherein R⁵, R⁶, u and v have the meaning as above. The values of m and n are selected fromm=0 and n=2, m=2 and n=0, m=1 and n=1 , m=0 and n=3, m=1 and n=2, m=2 and n=1 , m=3 and n=0, m=0 and n=4, m=1 and n=3, m=2 and n=2, m=3 and n=1 , m=4 and n=0, m=0 and n=5, m=1 and n=4, m=2 and n=3, m=3 and n=2, m=4 and n=1 , m=5 and n=0, m=1 and n=5, m=2 and n=4, m=3 and n=3, m=4 and n=2, m=5 and n=1 , m=2 and n=5, m=3 and n=4, m=4 and n=3, m=5 and n=2, m=3 and n=5, m=4 and n=4, m=5 and n=3, m=4 and n=5, m=5 and n=4, and m=5 and n=5; preferably m=2 and n=2.For example, when n= 2 and m=2, the ligand is defined according to formula (He).

In an embodiment, preferably the ligand is selected from compound defined by formula (Ila), (lib) and (lie). In a more preferred embodiment, the ligand is compound defined by formula (Ila).

In this description, ligand of formula (Ila) is designated as ligand L1 , ligand of formula (He) is designated as ligand L2, and ligand of formula (lib) is designated as ligand L3.

Process for preparing the ligand

Another aspect of the invention is a process for preparing the ligand of formula (II). The process for preparing the ligand of formula (II) comprises the reaction between compound of formula (Illa) or a combination of compounds of formula (Illa) and (lllb): with compound of formula (IV)

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-P^erfl^uorc>alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected fromlinear or branched C1-C5 alkyl, linear or branched O-(Ci-C₅)- alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, and substituted or unsubstituted phenyl; and more preferably beingt-Bu, 0 < m < 5 and 0 < n < 5 and n+m > 1 p, q, r and s are independently selected from 1 or 2 u and v are independently selected from 1 , 2, 3 or 4, in the presence of an organic base, preferably selected from pyridine, diisopropylethylamine, 1 -methylimidazole, butyllithium, and triethylamine (alone or in combination with catalytic amounts of 4-dimethylaminopyridine), and more preferably it is triethylamine. Said process may be carried out according to known procedures of synthetic organic chemistry, such as those disclosed in the supporting information included in Vidal- Ferran et a!., Chem. Eur. J., 2015, 21 , 11417-11426.

Compounds of formula (Illa) and (I I lb) may be prepared according to a known process, such as disclosed, for example, in US4769498, wherein phosphorus trichloride (PCI₃) is reacted with a substituted 1 ,1’-biphenyl-2,2’-diol compound.

Generally, symmetrical polyphosphite ligands, i.e., using only compound of formula (Illa), can be prepared by adding the diol (compound of formula IV) and chlorophosphite (compound of formula (Illa)) in either order. In a preferred embodiment, compound of formula (IV) is added slowly at a temperature comprised between 0 °C and 30 °C, preferably between 0 °C and 25 °C, and more preferably about 20 °C, to compound of formula (Illa) in the presence of the organic base, preferably triethylamine. In a preferred embodiment, the molar ratio of compound of formula (IV) to compound of formula (Illa) and to the organicbase is comprised between 1:2:2 and 1:5:5, preferably between 1 :2:2.2 and 1:3:4, and more preferably between 1:2.1 :2.3 and 1:2.2:2.4.

Asymmetrical polyphosphite ligands may be prepared in analogous way using a combination of compounds of formula (Ila) and (lllb).

Ligands of formula (II) in solid form may be easily separated from the reaction solution, recovered, and purified if desired, in any conventional manner employing standard techniques well-known by the skilled person in the field of organic synthesis, such as, for example, evaporation, recrystallization, chromatographic purification and/or filtration.

Process for the

Another aspect of the invention is a process for preparing said catalyst.

The supramolecular hydroformylation catalysts [Rh(CO)₂)(H)(L*(RA)_t)] can be indistinctly prepared from L, a rhodium (I) complex, and RA (if t= 1)) in a one-pot process i.e., preparation in situ), or in a stepwise manner employing identical starting materials. In the latter case, the reaction intermediates can be isolated (if desired), or further used in the next synthetic step without any purification. The synthetic strategies are summarized in Scheme I: Scheme I

Preparation in sitcr. RA, Rh(l) complex, CO/H₂

The Rh catalysts for hydroformylations ([Rh(CO)₂)(H)(L«RA)J or [Rh(CO)₂)(H)(L)]), they can be directly used from the prepared solutions, or they can be isolated as solids. These solids are stable for a few days if stored at low temperature (/.e., below 0 °C) under a CO atmosphere.

The process for preparing the catalyst of the invention comprises any one of the following alternatives a), b) or c): a) la)preparing a solution of a ligand (L), a regulation agent (RA), if present, and a rhodium (l)complex, in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of H₂/CO; b) lb) preparing a solution of a ligand (L) and a regulation agent (RA) in an inert solvent, and

2b) adding a solution a rhodium (I) complexin an inert solvent to the solution obtained in step 1b), and

3b) pressurizing the solution of step 2b) in an autoclave with a combination of H₂/CO; c)

1c) preparing a solution of a ligand (L), and a rhodium (I) complexin an inert solvent, 2c) pressurizing the solution of step 1c) in an autoclave with a combination of

H₂/CO, and optionally

3c) adding a regulation agent to the solution obtained in step 2c) under a pressure of H₂/CO.

The alternative a) represents an in situ preparation of the hydroformylation catalyst, whereas b) and c) represent two alternatives of the step-wise preparation of said catalyst.

Rhodium (I) complexes suitable in the process of the invention are any rhodium (l)complex, which is preferably selected from [Rh(K²O,O’-acac)(CO)₂], [Rh(K²O,O’-{2- ethylhexanoate})₃], [Rh(K²O,O’-acac)(r|²-1 ,5-cyclooctadiene)], [Rh(q²- norbornadiene)₂]BF₄, [{Rh(q²- 1 ,5-cyclooctadiene)(p-OMe)}₂], [{Rh(r|²-1 ,5- cyclooctadiene)(p-OAc)}₂], [{Rh( -CI)(n²-1,5-cyclooctadiene)}₂], and [Rh(q²-1 ,5- cyclooctadiene)(K²O,O’-2,2,6,6-tetramethyl-3,5-heptanedionate)]; and more preferably it is [Rh(K²O,O’-acac)(CO)₂]. Said complexes are well known by the skilled person in the art and are commercially available, for example, through the companies Strem or Ambeed. [{Rh(r|²-1 ,5-cyclooctadiene)(p-OAc)}₂] can be prepared as described in Lief al., Angew. Chem. Int. Ed. 2022, 61 , e202207917.[Rh(n²-1,5-cyclooctadiene)(K²0,0’-2, 2,6,6- tetramethyl-3,5-heptanedionate)] can be prepared as described in Stemmleret a/., Adv. Synth. Catal. 2007, 349, 1185-1198.

Preparation in situ

In an embodiment, the preparation in situ of the hydroformylation catalyst of the invention may be carried out by preparing a solution of a ligand (L), a regulation agent (RA), if present, and a rhodium (I) complex, as disclosed above, in an inert solvent, for example, selected from toluene, THF and mixtures thereof, and transferring said solution to an autoclave reactor, which is pressurized at a pressure comprised between 1bar (10⁵ Pa) and 20 bar(2x10⁶ Pa), preferably about 10 bar (10⁶ Pa) of H₂/CO in a ratio comprised between 1 :10 and 10:1 , preferably between 3:7 and 7:3, and more preferably 1 :1, and heated at a temperature comprised between 50°C and 120 °C, preferably between 60 °C and 100 °C. The mixture is stirred for a period of time comprised between 12 h and 24 h, preferably about 18 h. After that time, the reactor is cooled usually to room temperature, depressurized in a well-ventilated fume hood. The reaction mixture, comprising the catalyst of formula [Rh(CO)₂)(H)(L*RA)], is ready to be used for hydroformylations. In an embodiment, the solvent can also be removed in vacuo to dryness, obtaining a solid, which is stable if stored at low temperature (below 0 °C) under CO atmosphere.

Step-wise preparation A) Middle route in Scheme I

In an embodiment, the hydroformylation catalyst of the invention is prepared following the middle route in Scheme I, wherein, in a first step, a solution of a ligand (L) and a regulation agent (RA) in an inert solvent, for example, selected from toluene, THF and mixtures thereof, is stirred for a period of time of about 1 h. The reaction mixture is ready to be used in the next synthetic step, if desired, alternatively, the solvent may also be removed in vacuo to dryness, obtaining a solid (L*RA), which is stable if stored at low temperature (below 0 °C) under a N₂ atmosphere.

In a second step, the reaction mixture of the previous step comprising L*RAis transferred to an autoclave reactor, which is pressurized at a pressure comprised between 1 bar (10⁵ Pa) and 20 bar (2x10⁶ Pa), preferably about 10 bar (10⁶ Pa) of H₂/CO in a ratio comprised between 1 :10 and 10:1 , preferably between 3:7 and 7:3, and more preferably 1 :1 , and heated at a temperature comprised between 50°C and 120 °C, preferably between 60 °C and 100 °C. The mixture is stirred for a period of time comprised between 12 h and 24 h, preferably about 18 h. After that time, the reactor is cooled usually to room temperature, depressurized in a well-ventilated fume hood, and the catalyst of formula [Rh(CO)₂)(H)(L*RA)] is ready to be used for hydroformylations.

B) Bottom route in Scheme I

In an embodiment, the hydroformylation catalyst of the invention is prepared following the bottom route in Scheme I, wherein, in a first step a solution of ligand L and a rhodium (I) complex, as disclosed above, in an inert solvent, for example, selected from toluene, THF and mixtures thereof, is transferred to an autoclave reactor, which is pressurized at a pressure comprised between 1 bar (10⁵ Pa) and 20 bar (2x10⁶ Pa), preferably about 10 bar (10⁶ Pa) of H₂/CO in a ratio comprised between 1 :10 and 10:1 , preferably between 3:7 and 7:3, and more preferably 1 :1 , and heated at a temperature comprised between 50°C and 120 °C, preferably between 60 °C and 100 °C. The mixture is stirred for a period of time comprised between 12 h and 24 h, preferably about 18 h. The reactor was cooled to room temperature, depressurized in a well-ventilated fume hood and the reaction mixture, comprising a hydroformylation catalyst of formula [Rh(CO)₂(H)(L)], was ready to be used for hydroformylations, if desired. The solvent can also be removed in vacuo to dryness. The resulting solid is stable if stored at low temperature (below 0 °C) under a CO atmosphere.

In a second step, a regulation agent may be added as a solid onto a solution of [Rh(CO)₂(H)(L)], as prepared in the first step, under a pressure comprised between 1 bar (10⁵ Pa) and 2 bar (2x10⁵ Pa), preferably aboutl bar (10⁵ Pa) of H₂/CO in a ratio comprised between 1 :10 and 10:1 , preferably between 3:7 and 7:3, and more preferably 1 :1 , The mixture was allowed to stir under CO atmosphere for 1 hour, obtaining a hydroformylation catalyst of formula [Rh(CO)₂)(H)(L*RA)].

Use of the

Another aspect of the invention is use of the catalyst of the invention in hydroformylation reactions.

As disclosed in the Examples section, hydroformylation catalysts of the invention surprisingly show regioselective activity yielding selective formation of terminal aldehydes in front of branched aldehydes in combination with high conversion yields. Final regioselectivities (/.e., branched to linear ratio, abbreviated as b/l ratio) up to 2:98 in favor of the linear aldehydes are obtained with the ligand L1of formula (lla)and in the presence of a regulation agent.

The pressure of the reaction can be reduced to atmospheric pressure without loss of activity and regioselectivity, which makes these catalysts attractive for future industrial applications.

A main advantage of the hydroformylation catalyst of the invention is that while typical catalyst optimization towards the linear aldehyde for a substrate(s) relies on designing, synthesizing and testing new types of catalysts with structural variations on the catalyst via covalent chemistry being necessary to encompass the different types of olefins, the present invention is based on the use of the same ligand with structurally diverse external agents (/.e., regulation agents, RA) that modify the outcome of the reaction. The main advantage is the ease of synthesis of the whole library of catalysts (just by mixing the same ligand with an array of RAs and allowing the resulting mixtures to evolve to the catalysts) compared to covalently synthesizing a different “lead catalyst” for each substrate.

An important advantage of this approach also rests on the ability to modify the geometry of the catalytic site through supramolecular reversible interactions.

The hydroformylation reaction comprises any one of the following alternatives a) or b): a)

1a) preparing a solution of a ligand (L)defined by formula (II), a regulation agent (RA), a rhodium (I) complex, and an olefin in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of

H₂/CO; b) 1 b) adding an olefin to the hydroformylation catalyst according to formula (I) prepared in situ defined by any one of the formulas [Rh(CO)₂(H)(L)] or [Rh(CO)₂(H)(L«RA)], and

2b) pressurizing the solution of step 1 b) in an autoclave with a combination of H₂/CO.

In said process Lis a ligand of formula (II), RA is a regulation agent as defined above, and the preferred embodiments of the rhodium (I) complex are defined above.

The hydroformylation reaction takes place usually in an inert solvent, for example, selected from toluene, THF and mixtures thereof.

Pressurization of the solution comprising the catalyst and the olefin (substrate to hydroformylate) is generally carried out in an autoclave reactor, wherein the pressure is usually comprised between 1 bar (10⁵ Pa) and 80 bar (8x10⁶ Pa), preferably about 10 bar (10⁶ Pa) of H₂/CO in a ratio comprised between 1 :10 and 10:1 , preferably between 3:7 and 7:3, and more preferably 1 :1 , and heated at a temperature comprised between 25°C and 120 °C, preferably between 35 °C and 100 °C The mixture is stirred for a period of time comprised between 12 h and 24 h, preferably about 18 h. After that time, the reactor is cooled usually to room temperature, depressurized in a well-ventilated fume hood.

Conversion, chemo- and regioselectivity of the products arising from hydroformylation reaction conditions may be determined by GC analysis on an achiral stationary phase (HP-5) using dodecane as the internal standard.

Another aspect of the invention is a process for preparing aldehydes by a hydroformylation reaction, which comprises the reaction of an olefin with a combination of H₂/CO in the presence of a catalyst according to the invention.

The present invention is illustrated by the following embodiments:

1 .- A hydroformylation catalyst of formula (I) comprising a rhodium carbonyl hydride [Rh], a ligand Land, optionally, a regulation agent [RA]; wherein

[Rh] is Rh(CO)_xH, wherein x is 1 or 2, preferably x is 2;

[RA] is a regulation agent of formula M⁺A , wherein M⁺ is selected from an alkali metal cation and ammonium, and A is a non-coordinating anion; , , , , independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-perfluoroalkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected fromlinear or branched C1-C5 alkyl, linear or branched O-(Ci-C₅)- alkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, and substituted or unsubstituted phenyl; and more preferably they are t-Bu;

0 < m < 5; 0 < n < 5; n+m > 1 ; p, q, r and s are independently selected from 1 and 2; t is selected from 0 and 1 ; and u and v are independently selected from 1 , 2, 3 and 4.

2.- The hydroformylation catalyst according to embodiment 1 , wherein t=1.

3.- The hydroformylation catalyst according to any one of embodiment 1 or 2, wherein the equivalent ratio of [Rh]:[RA]:ligand is between 1 :1 :1 and 1 :2: 1.2, preferably between 1 :1.1 :1 and 1 :1.4: 1.1 , and more preferably between 1 :1.25:1.1 and 1 :1.35:1.1. 4.- The hydroformylation catalyst according to any one of embodiments 1 to3, wherein the regulation agent RA, M⁺ is an alkali metal cation, and more preferably M⁺ is selected from Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺.

5.- The hydroformylation catalyst according to any one of embodiments 1 to 4, wherein the non-coordinating anion A is selected from BF₄ , PF₆ ,CF₃COO and [B(3,5- (CF₃)₂C₆H₃)4] ", preferably being [B(3,5-(CF₃)₂C₆H₃)₄]T

6.- The hydroformylation catalyst according to any one of embodiments 1 to 5, wherein R¹ = R⁴ and R² = R³.

7.- The hydroformylation catalyst according to any one of embodiments 1 to 6, wherein: R¹, R², R³ and R⁴ are t-Bu; p, q, r and s are 2 ; R¹, R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings; 0 < m < 5 ; 0 < n < 5 ; n+m > 1 ; and wherein R⁵, R⁶, u and v have the meaning as above. In a preferred embodiment u and v are 0.

8.- The hydroformylation catalyst according to embodiment 7, wherein X is oxygen.

9.- The hydroformylation catalyst according to embodiment 8, wherein n+m is an integer from 2 to 5.

10.- The hydroformylation catalyst according to embodiment 9, wherein n+m is 2.

11.- The hydroformylation catalyst according to embodiment 9, wherein n+m is 5.

12.- The hydroformylation catalyst according to embodiment 7, wherein 13.- The hydroformylation catalyst according to embodiment 12, wherein values of m and n are selected fromm=0 and n=2, m=2 and n=0, m=1 and n=1 , m=0 and n=3, m=1 and n=2, m=2 and n=1 , m=3 and n=0, m=0 and n=4, m=1 and n=3, m=2 and n=2, m=3 and n=1 , m=4 and n=0, m=0 and n=5, m=1 and n=4, m=2 and n=3, m=3 and n=2, m=4 and n=1 , m=5 and n=0, m=1 and n=5, m=2 and n=4, m=3 and n=3, m=4 and n=2, m=5 and n=1 , m=2 and n=5, m=3 and n=4, m=4 and n=3, m=5 and n=2, m=3 and n=5, m=4 and n=4, m=5 and n=3, m=4 and n=5, m=5 and n=4, and m=5 and n=5; preferably m=2 and n=2.

14.- A process for preparing the catalyst of formula (I) comprising any one of the following alternatives a), b) or c): a) la) preparing a solution of a ligand L, a regulation agent (RA), if present, and a rhodium (I) complex, in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of H₂/CO; b) l b) preparing a solution of a ligand Land a regulation agent (RA) in an inert solvent, and

2b) adding a solution of a rhodium (I) complex in an inert solvent to the solution obtained in step 1b), and

3b) pressurizing the solution of step 2b) in an autoclave with a combination of H₂/CO; c) lc) preparing a solution of a ligand L, and a rhodium (I) complex, in an inert solvent, 2c) pressurizing the solution of step 1c) in an autoclave with a combination of H₂/CO, and optionally

15.- The process according to embodiment 14, wherein the rhodium (I) complex is selected from [Rh(K²O,O’-acac)(CO)₂], [Rh(K²O,O’-{2-ethylhexanoate})₃], [Rh(K²O,O’- acac)(r|²-1 ,5-cyclooctadiene)], [Rh(q²- norbornadiene)₂]BF₄, [{Rh(r|²-1 ,5-cyclooctadiene)(p- OMe)}₂], [{Rh(r|²-1 ,5-cyclooctadiene)(p-OAc)}₂], [{Rh( -CI)(n²-1 ,5-cyclooctadiene)}₂], and [Rh(r|²-1 ,5-cyclooctadiene)(K²O,O’-2,2,6,6-tetramethyl-3,5-heptanedionate)]; preferably being[Rh(K²O,O’-acac)(CO)₂]. 16.- Use of the catalyst of formula (l)as defined in any one of embodimentsi to 13 in a hydroformylation reaction.

17.- The use according to embodiment 16, wherein the hydroformylation reaction comprises any one of the following alternatives a) or b): a) la) preparing a solution of a ligand Ldefined by formula (II), a regulation agent (RA), a Rh complex, and an olefin in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of H₂/CO; b) l b) adding an olefin to the hydroformylation catalyst prepared in situ defined by any one of the formulas [Rh(CO)₂(H)(L)]or [Rh(CO)₂(H)(L«RA)J, and

2b) pressurizing the solution of step 1 b) in an autoclave with a combination of H₂/CO, wherein the ligand Lis according to any one of embodiments 14 to 21 , the regulation agent RA is as defined in any one of embodiments4 and 5, and the Rh complex is as defined in embodiment 15. wherein

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-perfluoroalkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected from linear or branched C1-C5 alkyl, linear or branched O-(C C₅)-alkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, and substituted or unsubstituted phenyl;more preferably beingt-Bu;

0 < m < 5; 0 < n < 5; n+m > 1 ; p, q, r and s are independently selected from 1 and 2; u and v are independently selected from 0, 1 , 2, 3 and 4; and

19.- The ligand Laccording to embodiment 18, wherein R¹ = R⁴ and R² = R³.

20.- The ligandL according to embodiment 19, wherein: R¹, R², R³ and R⁴ are t-Bu; p, q, r and s are 2; R¹, R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings; 0 < m <

In a preferred embodiment u and v are 0.

21 The ligand Laccording to embodiment 20, wherein X is oxygen.

22.- The ligand Laccording to embodiment 20, whereinn+m is an integer between 2 and 5;n+m preferably being 2 or 5.

23.- The ligand Laccording to embodiment 22, wherein values of m and n are selected from: m=0 and n=2, m=2 and n=0, m=1 and n=1 , m=0 and n=3, m=1 and n=2, m=2 and n=1 , m=3 and n=0, m=0 and n=4, m=1 and n=3, m=2 and n=2, m=3 and n=1 , m=4 and n=0, m=0 and n=5, m=1 and n=4, m=2 and n=3, m=3 and n=2, m=4 and n=1 , m=5 and n=0, m=1 and n=5, m=2 and n=4, m=3 and n=3, m=4 and n=2, m=5 and n=1 , m=2 and n=5, m=3 and n=4, m=4 and n=3, m=5 and n=2, m=3 and n=5, m=4 and n=4, m=5 and n=3, m=4 and n=5, m=5 and n=4, and m=5 and n=5; preferably m=2 and n=2.

24.- The ligand Laccording to embodiment 18, whichhas a formula selected from (Ila), (lib) and (lie):

25.- A process for preparing the ligandLof formula (ll)as defined in embodiment 18, comprising the reaction between a compound of formula (Illa) or a combination of compounds of formula (Illa) and (lllb) lb) with compound of formula (IV) wherein

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-perfluoroalkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected from linear or branched C1-C5 alkyl, linear or branched O-(C C₅)-alkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, and substituted or unsubstituted phenyl; and more preferably they are t-Bu ;

0 < m < 5 ; 0 < n < 5 ; n+m > 1 ; p, q, r and s are independently selected from 1 and 2; and u and v are independently selected from 1 , 2, 3 and 4; in the presence of an organic base, preferably selected from pyridine, diisopropylethylamine, 1 -methylimidazole, butyllithium, and triethylamine(alone or in combination with catalytic amounts of 4-dimethylaminopyridine). Preferably the organic base is triethylamine.

26.- A process for preparing aldehydes by a hydroformylation reaction, wherein it comprises the reaction of an olefin with a combination of H₂/CO in the presence of a catalyst according to any one of embodiments 1 to 13. EXAMPLES

Preparative example: Preparation of alkali metal and ammonium BArF salts

The syntheses of LiBArF, KBArF, RbBArF and CsBArF have been carried out following the procedure reported in Carreras et al., RSC Adv., 2018, 7, 32833-32841. The synthesis of and EtNH₃BArF has been carried out following the procedure reported in Ganeshpureef a/., J. Mol. Catal. A: Chem. 2008, 279, 182-186. NaBArF was purchased from Apollo Scientific Ltd. The abbreviation BArF responds to the anion [B(3,5- (CF₃)₂C₆H₃)₄]’.

Example 1 : Preparation ofbisphosphite ligand L1

Bisphosphite Ligand L1 a) Synthesis of 3,3',5,5'-tetra- terf-butylbiphenyl-2,2'-diyl chlorophosphite (2)

The preparation of 3,3', 5,5'-tetra-terf-butylbiphenyl-2 ,2'-diyl chlorophosphite was performed by slightly varying a reported procedure in Buisman et al., Tetrahedron: Asymmetry, 1993, 4, 1625-1634.

In a flame-dried Schlenk flask, 3,3',5,5'-tetra-terf-butyl-2,2'-dihydroxybiphenyl (1) (2.01 g, 4.8 mmol, 1.01 equiv.) was weighted, and then azeotropically dried with toluene (3 x 10 mL). 30 mL of anhydrous toluene (SPS; abbreviation that refers to Solvent Purification System) were added to the flask. Another flame-dried Schlenk flask was placed in the glove box, and 0.51 mL of PCI₃ (5.82 mmol, 1.22 equiv.) were transferred to the flask. 30 mL of anhydrous toluene were also added to the Schlenk flask. Finally, triethylamine (1.75 mL, 12.6 mmol, 2.64 equiv.) was syringed into the solution. The "Bl POL" solution at room temperature was slowly (ca. 45-60 min) added via cannula to the PCI₃solution (0°C). Then, the mixture was stirred for 16 hours at room temperature. After this, the reaction mixture was filtered to another flame-dried Schlenk flask. The filtrate was evaporated to dryness under vacuum to give a yellow solid (1.97 g, quantitative yield). This chlorophosphite (2) was used with no purification in the next synthesis step. Spectroscopic data for this compound were in agreement with those already reported in the literature (Carreras et al., Org. Chem. Front., 2020, 7, 1626-1634). b)Synthesis of Bisphosphite Ligand L1

In a flame-dried Schlenk, a solution of the corresponding chlorophosphite 2 (1.97 g, 4.15 mmol, 2.2 equiv.) in 30 mL of anhydrous toluene (SPS) was prepared and then triethylamine (635 pL, 4.52 mmol, 2.4 equiv.) was added dropwise to the former solution. In another flame-dried Schlenk, a solution of tetraethylene glycol (331 mL, 1.89 mmol, 1.0 equiv.), previously azeotropically dried with toluene (3 x 5 mL), in 30 mL anhydrous toluene was prepared. Tetraethylene glycol was slowly added via cannula to the chlorophosphite solution (ca. 30 min) at room temperature. Then, the mixture was stirred for 16 hours. After this, the turbid reaction mixture was filtered through celite® and the filtrate was evaporated to dryness to give the crude as a white-yellow solid. The product was then purified by filtration through a pad of basic alumina, using dichloromethane as the solvent, to give the pure bisphosphite(LI) as white solid (1.86 g, 92% isolated yield, melting point 92 °C, HRMS (ESI⁺) m/z calcd. for C64H₉₇O9P2⁺ [M+H]⁺ 1071.6602, found 1071.6597). Spectroscopic data of the compoundwere in agreement with the proposed structure.

Example 2: Preparation of bisphosphite ligand L2

The synthetic routes to the target compounds 4 and 6 (steps 1 and 2, respectively) were previously reported in Vidal-Ferran et al., Chem. Eur. J., 2015, 21 , 11417-11426. a) Synthesis of2-(2-(2-hydroxyethoxy)ethoxy)ethyl 4-methylbenzenesulfonate(4)

The synthetic route to the target compound 4 (step 1) was previously reported in Vidal-Ferran et a!., Chem. Eur. J., 2015, 21 , 11417-11426.

The monotosylated product 4 was prepared from a solution of triethylene glycol 3 (7.83 mL, 55.5 mmol, 1 equiv.) and triethylamine (4.0 mL, 28.5 mmol, 0.514 equiv.) in CH₂CI₂ (100 mL). Then, tosyl chloride (2.71 g, 13.9 mmol, 0.251 equiv.) was added in one portion. The resulting mixture was stirred for two hours at room temperature. After washing with 100 mL of 1 M KHSO₄ and 5% NaHCO₃ and drying over Na₂SO₄, the product was obtained by purification by flash column chromatography over silica gel using AcOEt as eluent. The pure monotosylated product 4 was obtained as a clear, colorless oil (2.68 g, 16% isolated yield). Spectroscopic data for this compound were in agreement with the reported ones. b) Synthesis of2,2'-((((([1 ,1'-biphenyl]-2,2'-diylbis(oxy))bis(ethane-2,1-diyl))bis(oxy)) bis(ethane-2, 1 -diyl))bis(oxy))bis(ethan-1 -ol)(6)

The synthetic route to the target compound 6 (step 2) was previously reported in Vidal-Ferran et a/., Chem. Eur. J., 2015, 21 , 11417-11426.

[1 , 1 '-Biphenyl]-2,2'-diol 5 (0.934 g, 4.96 mmol, 1 equiv), the monotosylated triethyleneglycol 4 (3.02 g, 9.93 mmol, 2 equiv.) and K₂CO₃ (2.98 g, 21.3 mmol) were introduced into an oven-dried 100 mL two-necked flask. Then, a condenser was connected to the flask and three vacuum-nitrogen cycles were performed. Anhydrous acetonitrile (46 mL) was syringed into the flask under nitrogen atmosphere. The resulting reaction mixture was heated at reflux and stirred for 60 hours. Then, the reaction mixture was cooled, allowed to reach room temperature, and concentrated in vacuo. The resulting residue was finally purified by flash column chromatography on silica gel using cyclohexane/acetone as eluents (50:50 to 30:70) to yield the desired product 6 as a colorless viscous oil (2.1 g, 94% isolated yield). Spectroscopic data for this compound were in agreement with the reported ones. c) Synthesis of Bisphosphite Ligand L2

In a flame dried Schlenk, a solution of the corresponding chlorophosphite 2 (2.61 g, 5.49 mmol, 2.17 equiv.) in 35 mL of anhydrous toluene (SPS) was prepared. Triethylamine (1.07 mL, 7.59 mmol, 3 equiv.) was then added dropwise. In another flame dried Schlenk, a solution of diol 6 (1.14 g, 2.53 mmol, 1.0 equiv.), previously azeotropically dried with toluene (3 x 5 mL), in 35 mL anhydrous toluene (SPS) was prepared. The diol 6 was slowly added via cannula to the chlorophosphite solution (ca. 30 min) at room temperature. Then, the mixture was stirred for 18 hours. After this, the turbid reaction mixture was filtered through celite® and the filtrate was evaporated to dryness to give the crude as a white-yellow solid. The product was then purified by filtration through a pad of basic alumina, using dichloromethane as the solvent, to give the pure bisphosphite L2 as white solid (2.98 g, 89% isolated yield, melting point 81 °C, HRMS (ESI⁺) m/z calcd. for C₈oH₁₁₂NaOi₂P2⁺ [M+Na]⁺ 1349.7521 , found 1349.7527). Spectroscopic data of the compound were in agreement with the proposed structure.

Example 3: Preparation of bisphosphite ligand L3 L3

In a flame dried Schlenk, a solution of the corresponding chlorophosphite 2 (1.32 g, 2.73 mmol, 2.2 equiv.) in 12.5 mL of anhydrous toluene (SPS) was prepared.

Triethylamine (418 pL, 2.98 mmol, 2.4 equiv.) was then added dropwise. In another flame dried Schlenk, a solution of heptaethylene glycol (359 pL, 1.24 mmol, 1.0 equiv.), previously azeotropically dried with toluene (3 x 5 mL), in 5 mL anhydrous toluene (SPS) was prepared. Heptaethylene glycol was slowly added via cannula to the chlorophosphite solution (ca. 30 min) at room temperature. Then, the mixture was stirred for 16 hours. After this, the turbid reaction mixture was filtered through celite® and the filtrate was evaporated to dryness to give the crude as a white-yellow solid. The product was then purified by filtration through a pad of basic alumina, using dichloromethane as the solvent, to give the pure bisphosphite L3 as white solid (100 mg, 97% of purity by ³¹ P NMR, 6.6% isolated yield). Spectroscopic data of the compound were in agreement with the proposed structure.

Bisphosphite L1 [Rh(CO)₂(H)(L1 -KBArF)]

A 50 mM solution of bisphosphite ligand L1 (1 equiv.), KBArF (1.3 equiv.) and [Rh(K²O,O’-acac)(CO)₂] (1 equiv.) in toluene/THF (97:3 v/v) was transferred to a 25 mL autoclave reactor, which was pressurized at 10 bar H₂/CO (1 :1) and heated at 60 °C. The mixture was allowed to stir for 18 hours. The reactor was cooled to room temperature, depressurized in a well-ventilated fume hood and the reaction mixture was ready to be used for hydroformylations, if desired. The complex was characterized by recording the spectrum under N₂ after depressurizing. HRMS (MALDI-TOF) m/z calcd. for C₆4H9₆O₉P₂Rh⁺ [M-KBArF-2CO-H]⁺ 1173.5579, found 1173.5584.

The solvents can also be removed in vacuo to dryness. The resulting solid is stable if stored at low temperature (below 0 °C) under a CO atmosphere.

To characterize the complex by NMR-techniques, the synthetic protocol described above was performed using deuterated solvents. The solution was transferred to a 5 mm HP-NMR sapphire tube. The tube was pressurized at 10 bar H₂/CO (1 :1) and the HP-NMR spectra were collected at 25 °C. Spectroscopic data obtained from this solution were in agreement with the quantitative formation of the [Rh(CO)₂(H)(L1 •KBArF)] complex.

A 50 mM solution of bisphosphite ligand L1 (1 equiv.), CsBArF (1.3 equiv.) and [Rh(K²O,O’-acac)(CO)₂] (1 equiv.) in toluene/THFin (97:3 v/v) was transferred to a 25 mL autoclave reactor, which was pressurized at 10 bar H₂/CO (1 :1) and heated at 60 °C. The mixture was allowed to stir for 18 hours. The reactor was cooled to room temperature, depressurized in a well-ventilated fume hood and the reaction mixture was ready to be used for hydroformylations, if desired. The complex was characterized by recording the spectrum under N₂ after depressurizing. HRMS (MALDI-TOF) m/z calcd. for C₆4H9₆O₉P₂Rh⁺ [M-CsBArF-2CO-H]⁺ 1173.5579, found 1173.5583.

To characterize the complex by NMR-techniques, the synthetic protocol described above was performed using deuterated solvents. The solution was transferred to a 5 mm HP-NMR sapphire tube. The tube was pressurized at 10 bar H₂/CO (1 :1) and the HP-NMR spectra were collected at 25 °C. Spectroscopic data obtained from this solution were in agreement with the quantitative formation of the [Rh(CO)₂(H)(L1 •CsBArF)].

A 50 mM solutionof bisphosphite ligand L2 (1 equiv.), KBArF (1.3 equiv.) and [Rh(K²O,O’-acac)(CO)₂] (1 equiv.) in toluene-d₈/THF-d₈ (97:3 v/v) was transferred to a 25 mL autoclave reactor, which was pressurized at 10 bar H₂/CO (1 :1) and heated at 60 °C. The mixture was allowed to stir for 18 hours. The reactor was cooled to room temperature, depressurized in a well-ventilated fume hood and the reaction mixture was ready to be used for hydroformylations, if desired. The complex was characterized by recording the spectrum under N₂ after depressurizing. MS (MALDI-TOF) m/z calcd. for C₈oH₁₁₂Oi₂P₂Rh⁺ [M-KBArF-2CO-H]⁺ 1429.7, found 1429.5.

To characterize the complex by NMR-techniques, the synthetic protocol described above was performed using deuterated solvents. The solution was transferred to 5 mm HP-NMR sapphire tube. The tube was pressurized at 10 bar H₂/CO (1 :1) and the HP-NMR spectra were collected at 25 °C. MS samples were immediately recorded under N₂ after depressurizing the autoclave. Spectroscopic data obtained from this solution were in agreement with the quantitative formation of the [Rh(CO)₂(H)(L2*KBArF)] Example 7:Step-wise preparation of catalyst [Rh(CO)₂(H)(L1 «KBArF)l a) Preparation of LT KBArF (1^st step, middle route in Scheme I)

A 50 mM solution of bisphosphite ligand L1 (1 equiv.) and KBArF (2.0 equiv.) in toluene/THF (97:3 v/v) were stirred for 1 h. The reaction mixture was ready to be used in the next synthetic step, if desired. The solvents can also be removed in vacuo to dryness The resulting solid is stable if stored at low temperature (below 0 °C) under a N₂ atmosphere.

To characterize the complex by NMR-techniques, the synthetic protocol described above was performed using deuterated solvents. The solution was transferred to a 5 mm NMR tube. The NMR spectra were immediately collected at 25 °C under N₂ atmosphere. Spectroscopic data obtained from this solution were in agreement with the quantitative formation of the LTKBArF. b) Preparation of [Rh(CO)₂(H)(L1 *KBArF)]from LTKBArF (2^nd step, middle route in Scheme I)

The reaction mixture of the previous step was transferred to a 25 mL autoclave reactor, which was pressurized at 10 bar H₂/CO (1 :1) and heated at 60°C. The mixture was allowed to stir for 18 hours. The reactor was cooled to room temperature, depressurized in a well-ventilated fume hood and characterized by MS and NMR. Spectroscopic data were in agreement with those already described for this complex in the section corresponding to the preparation in situ of rhodium(l) complexes. a') Preparation of [Rh(CO)₂(H)(L1)](1^st step, bottom route in Scheme I)

A 50 mM solution of bisphosphite ligand L1 (1 equiv.) and [Rh(K²O,O’-acac)(CO)₂] (1 equiv.) in toluene/THF (97:3 v/v) was transferred to a 25 mL autoclave reactor, which was pressurized at 10 bar of H₂/CO (1 :1) and heated at 60°C. The mixture was allowed to stir for 18 hours. The reactor was cooled to room temperature, depressurized in a well- ventilated fume hood and the reaction mixture was ready to be used for hydroformylations, if desired. The complex was characterized by recording the spectrum under N₂ after depressurizing. HRMS (MALDI-TOF) m/z calcd. for C₆4Hg₆0gP₂Rh⁺ [M- 2CO-H]⁺ 1173.5579, found 1173.5569.

To characterize the complex by NMR-techniques, the synthetic protocol described above was performed using deuterated solvents. The solution was transferred to a 5 mm HP-NMR sapphire tube. The tube was pressurized at 10 bar H₂/CO (1 :1) and the HP-NMR spectra were collected at 25 °C. Spectroscopic data obtained from this solution were in agreement with the quantitative formation of the [Rh(CO)₂(H)(L1)]. b') Preparation of [Rh(CO)₂(H)(L1 *KBArF)]from[Rh(CO)2(H)(L1 )] (2^nd step, bottom route in Scheme I)

[Rh(CO)₂(H)(L1)] [Rh(CO)₂(H)(KBArF«L1)]

KBArF (1.3 equiv.) was added as a solid onto the 50 mM solution of [Rh(CO)₂(H)(L1)] prepared in the previous section under 1 bar of H₂/CO (1 :1). The mixture was allowed to stir under CO atmosphere for 1 hour. The complex was characterized by MS and NMR. Spectroscopic data from this solution were in agreement with the quantitative formation of [Rh(CO)₂(H)(L1 •KBArF)] and in agreement with those already described for this complex in the section corresponding to the preparation in situ of rhodium(l) complexes.

Example 8:Rh-mediated asymmetric hydroformylation of 2-ethyl-2-vinyl-1 ,3-dioxolane

Aldehyde products

2-Ethyl-2-vinyl- 1 ,3-dioxolane Branched (b) Linear (I)

The Rh-mediated asymmetric hydroformylation was performed according to the following general procedure.

In a vial with a magnetic bar, stock solutions of bisphosphite ligands L1 , L2 or L3 (1.20 mol%), BArF salt (1.56 mol%), and [Rh(K²O,O’-acac)(CO)₂] (1.0 mol%) were added. The corresponding substrate (1 mmol), dodecane (30 mol%, internal standard) and toluene/THF (97:3 v/v) were charged to provide the desired final concentration of 0.26 M.

Alternatively, 1 mol% of the supramolecular catalyst prepared in situ (according to analogous procedures of Examples 4 to 6) was placed in a vial with a magnetic bar. The corresponding substrate (1 mmol), dodecane (30 mol%, internal standard) and toluene/THF (97:3 v/v) were charged to provide the desired final concentration of 0.26 M. Once the reaction mixture had been loaded, the vial vessel was then placed into one of the holes of a steel autoclave reactor (HEL Cat-7parallel pressure multireactor) and taken out of the glove box. The autoclave was purged three times with H₂/CO (1 :1) (pressure not higher than 10 bar) and finally, the autoclave was pressurized with H₂/CO (1 :1) to the desired pressure (10 bar). The reaction mixture was stirred at 60°C for 18 hours. The reaction was cooled and the pressure was carefully released in a well- ventilated hood. Conversion, chemo- and regio-selectivity of the products arising from hydroformylation reaction conditions were determined by GC analysis on an achiral stationary phase (HP-5) using dodecane as the internal standard. In the case of 2-ethyl-2-vinyl- 1 ,3-dioxolane the hydroformylation was performed in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1:1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table I:

Table I ^aThesehydroformylations were performed with 1 mol% of the supramolecular catalysts prepared in advance (according to the recipe disclosed in Example 7). The results in terms of conversion and selectivity were in agreement with those obtained with the catalyst prepared in situ (results indicated in this table in entries 4 and 6) ± 1%.

Example 9:Rh-mediated asymmetric hydroformylation of hex-1 -ene

Aldehyde products -ene

C₃-Aldehyde

Isomerization products Hydrogenation product

The Rh-mediated asymmetric hydroformylation of hex-1 -ene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table II.

Table II Example 10:Rh-mediated asymmetric hydroformylation of hept-1-ene

Aldehyde products

Hept-1-ene

C₃-Aldehyde C₄- Aldehyde

Isomerization products Hydrogenation product

The Rh-mediated asymmetric hydroformylation of hept-1-ene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table III.

Table III Example 11 :Rh-mediated asymmetric hydroformylation of oct-1 -ene

Aldehyde products

Oct-1 -ene C₃-Aldehyde C₄-Aldehyde

Isomerization products Hydrogenation product

The Rh-mediated asymmetric hydroformylation of oct-1 -ene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table IV.

Table IV Example 12:Rh-mediated asymmetric hydroformylation of undec-1-ene

Aldehyde products

Undec-1 -ene

C₃-Aldehyde

Isomerization products Hydrogenation product The Rh-mediated asymmetric hydroformylation of undec-1-ene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1:1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table V. Example 13:Rh-mediated asymmetric hydroformylation of allylbenzene

Aldehyde products Branched (b) Linear (I)

Isomerization products Hydrogenation product

The Rh-mediated asymmetric hydroformylation of allylbenzene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1:1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table VI.

Table VI

2,4,4-trimethylpent-1-ene

Isomerization Hydrogenation product product

The Rh-mediated asymmetric hydroformylation of 2,4,4-trimethylpent-1-ene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 100°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table VII.

Table VII aThese hydroformylations were performed with 1 mol% of the supramolecular catalysts prepared in advance (according to the recipe disclosed in Example 7). The results in terms of conversion and selectivity were in agreement with those obtained with the catalyst prepared in situ (results indicated in this table in entries 4 and 6) ± 2%. Example 15:Rh-mediated asymmetric hydroformylation of (+)-8-citronellene

Aldehyde products

Isomerization Hydrogenation product product

The Rh-mediated asymmetric hydroformylation of (+)-p-citronellene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1:1); 35°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table VIII.

Table VIII

Aldehyde products

Branched (b) Linear (I)

Isomerization products

Eugenol

The Rh-mediated asymmetric hydroformylation of eugenol was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table IX.

Table IX

Example 17: Rh-mediated asymmetric hydroformylation of (3-methylbut-3-en-1-yl)benzene

Aldehyde products

(3-methylbut-3-en-1 -yl)benzene

Isomerization Hydrogenation products product

The Rh-mediated asymmetric hydroformylation of (3-methylbut-3-en-1-yl)benzene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 100°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table X.

Table X

Example 18: Rh-mediated asymmetric hydroformylation of 1-((2-methylallyl)oxy)octane Aldehyde products

1-((2-methylallyl)oxy) octane

Isomerization Hydrogenation products product

The Rh-mediated asymmetric hydroformylation of 1-((2-methylallyl)oxy)octane was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 100°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table XI.

Table XI

19: Rh-mediated of 1-i vDbenzene

Aldehyde Products

The Rh-mediated asymmetric hydroformylation of 1-isopropyl-3-(prop-1-en-2- yl)benzene was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO (1 :1); 100°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table XII.

Table XII

20: Rh-mediated under of H₂/CO and KBArF as Regulation Agent

Aldehyde products

Substrates

Isomerization Hydrogenation products product

The Rh-mediated asymmetric hydroformylation of the substrates was performed according to the general procedure, as disclosed in Example 8, in a parallel autoclave, wherein the reaction conditions were: [substrate] = 0.26 M; stirring rate = 800 rpm; 10 bar H₂/CO; 60°C, 18h.

Conversion, ratio and selectivity were determined by GC using dodecane as an internal standard. Results are shown in Table XIII.

Table XIII

Example 21 :Pd-mediated isomerization and Rh-mediated asymmetric hydroformylation tandem reaction a) Octenes

Aldehyde products

A: Oct-1 -ene

B: (E)-Oct-2-ene C₃-Aldehyde C₄-Aldehyde

C: (Z)-Oct-2-ene

D: (E)-Oct-3-ene

E: (E)-Oct-4-ene Isomerization products Hydrogenation product

F: (Z)-Oct-4-ene

The Pd-mediated isomerization Rh-mediated asymmetric hydroformylation tandem reaction of an equimolecular mixture of octenes was performed by adding stock solutions of bisphosphite ligand L1 (1.20 mol%), BArF salt (3.6 mol%), [Rh(K²O,O’-acac)(CO)₂] (1.0 mol%), [Pd(t-Bu₃P)₂] (0.5 mol%) and [Pdl₂] (0.5 mol%) in a vial with a magnetic bar. The corresponding mixture of alkenes (overall molar amount of octenes = 1 mmol), dodecane (30 mol%, internal standard) and toluene/THF (97:3 v/v) were charged to provide the desired final concentration of 0.26 M.

Once the reaction mixture was loaded, the vial vessel was then placed into one of the holes of a steel autoclave reactor (HEL Cat-7 parallel pressure multireactor) and taken out of the glove box. The procedure from this point, was analogous to that reported for hydroformylations (see Example 8 above).

Selectivity and ratio were determined by GC using dodecane as an internal standard. Results are shown in Table XIV.

Table XIV b) Heptenes Aldehyde products

A: Hept-1 -ene

B: (E)-Hept-2-ene C₃-Aldehyde C^-Aldehyde

C: (Z)-Hept-2-ene

D: (E)-Hept-3-ene (equimolar amounts) Isomerization products Hydrogenation product

The Pd-mediated isomerization Rh-mediated asymmetric hydroformylation tandem reaction of an equimolecular mixture of heptenes was performed according to the procedure, as disclosed above in section a) of this Example. Selectivity and ratio were determined by GC using dodecane as an internal standard. Results are shown in Table XV.

Table XV c) Hexenes

Aldehyde products

C_rAldehyde C₂-Aldehyde (Linear)

A: Hex-1 -ene

B: (E)-Hex-2-ene C₃- Aldehyde

C: (Z)-Hex-2-ene

D: (E)-Hex-3-ene

E: (Z)-Hex-3-ene Isomerization products Hydrogenation product (equimolar amounts) The Pd-mediated isomerization Rh-mediated asymmetric hydroformylation tandem reaction of an equimolecular mixture of hexenes was performed according to the procedure as disclosed above in section a) of this Example.

Selectivity and ratio were determined by GC using dodecane as an internal standard. Results are shown in Table XVI.

Table XVI d) Allylbenzenes

Aldehyde products

A: Allylbenzene

B: frans-p-methylstyrene

C: c/s-p-methylstyrene

(equimolar amounts) Isomerization products Hydrogenation product

The Pd-mediated isomerization Rh-mediated asymmetric hydroformylation tandem reaction of an equimolecular mixture of allylbenzenes was performed according to the procedure as disclosed above in section a) of this Example.

Selectivity and ratio were determined by GC using dodecane as an internal standard. Results are shown in Table XVII.

Table XVII

Claims

1.- A hydroformylation catalyst of formula (I) comprising a rhodium carbonyl hydride [Rh], a ligand L and, optionally, a regulation agent [RA]; wherein:

[Rh] is Rh(CO)_xH, wherein x is 1 or 2, and preferably x is 2;

[RA] is a regulation agent selected from a salt of formula M⁺ A , wherein M⁺ is selected from an alkali metal cation and ammonium, and A is a non-coordinating anion; the ligand Lhas formula (II)

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-P^erfl^uorc>alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and substituted or unsubstituted biphenyl; preferably they are selected from linear or branched C1-C5 alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched O-(Ci-C8)-p^erfluoroalkyl , and substituted or unsubstituted phenyl;more preferably beingt-Bu;

2.- The catalyst according to claim 1 , wherein M⁺ is an alkali metal cation; preferably Li⁺, Na⁺, K⁺, Rb⁺, or Cs⁺.

3.- The catalyst according to claim 1 or 2, wherein A is selected from BF₄ , PF₆ , CF₃COO or [B(3,5-(CF3)₂C6H₃)4] , the latter abbreviated as BArF; preferably

A beingBArF.

4.- The catalyst according to any one of claims 1 to 3, wherein: R¹, R², R³ and R⁴ are t-Bu; p, q, r and s are 2; R¹ , R², R³ and R⁴ are in positions 3, 5, 3’ and 5’ of the biphenyl rings; 0 preferably u and v being 0.

5.- The catalyst according to claim 4, wherein X is oxygen.

6.- The catalyst according to claim 5, wherein n+m is an integer from 2 to 5.

7.- The catalyst according to claim 6, wherein n+m is 2.

8.- The catalyst according to claim 4, wherein

9.- The catalyst according to claim 8, wherein values of m and n are selected from m=0 and n=2, m=2 and n=0, m=1 and n=1 , m=0 and n=3, m=1 and n=2, m=2 and n=1 , m=3 and n=0, m=0 and n=4, m=1 and n=3, m=2 and n=2, m=3 and n=1 , m=4 and n=0, m=0 and n=5, m=1 and n=4, m=2 and n=3, m=3 and n=2, m=4 and n=1 , m=5 and n=0, m=1 and n=5, m=2 and n=4, m=3 and n=3, m=4 and n=2, m=5 and n=1 , m=2 and n=5, m=3 and n=4, m=4 and n=3, m=5 and n=2, m=3 and n=5, m=4 and n=4, m=5 and n=3, m=4 and n=5, m=5 and n=4, and m=5 and n=5; preferably being m=2 and n=2.

10.- A process for preparing a hydroformylation catalyst of formula (I) as defined in any one of claims 1-9, comprising any one of the following alternatives a), b) or c): a) la) preparing a solution of a ligand (L), a regulation agent (RA), if present, and a rhodium (I) complex, in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of H₂/CO; b) l b) preparing a solution of a ligand (L) and a regulation agent (RA) in an inert solvent, and

3b) pressurizing the solution of step 2b) in an autoclave with a combination of H₂/CO; c) lc) preparing a solution of a ligand (L), and a rhodium (I) complex, in an inert solvent,

2c) pressurizing the solution of step 1c) in an autoclave with a combination of

H₂/CO, and optionally

11.- The process according to claim 10, wherein the rhodium (I) complex is selected from [Rh(K²O,O’-acac)(CO)₂], [Rh(K ²O,O’-{2-ethylhexanoate})₃], [Rh(K²O,O’-acac)(r|²-1 ,5- cyclooctadiene)], [Rh(q²- norbornadiene)₂]BF₄, [{Rh(r|²-1 ,5-cyclooctadiene)(p-OMe)}₂], [{Rh(r|²-1 ,5-cyclooctadiene)(p-OAc)}₂], [{Rh( -CI)(n²-1 ,5-cyclooctadiene)}₂], and [Rh(q²- 1 ,5-cyclooctadiene)(K²O,O’-2,2,6,6-tetramethyl-3,5-heptanedionate)]; the rhodium (I) complex preferably being[Rh(K²O,O’-acac)(CO)₂].

12.- Use of a catalyst of formula (I) as defined in any one of the claims 1 to 9, in a hydroformylation reaction.

13.- Use according to claim 12, wherein the hydroformylation reaction comprises any one of the following alternatives a) or b): a) la) preparing a solution of a ligand (L) defined by formula (II), a regulation agent (RA), a Rh complex, and an olefin in an inert solvent, and

2a) pressurizing the solution of step 1a) in an autoclave with a combination of H₂/CO; b) l b) adding an olefin to the hydroformylation catalyst prepared in situ defined by any one of the formulas [Rh(CO)₂(H)(L)J or [Rh(CO)₂(H)(L«RA)J, and

2b) pressurizing the solution of step 1 b) in an autoclave with a combination of wherein:

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-perfluoroalkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and substituted or unsubstituted biphenyl; preferably selected from linear or branched C1-C5 alkyl, linear or branched O-(C C₅)-alkyl, linear or branched O-(Ci-C₈)-perfluoroalkyl, and substituted or unsubstituted phenyl;more preferably beingt-Bu ;

0 < m < 5; 0 < n < 5; n+m > 1 ; p, q, r and s are independently selected from 1 and 2; u and v are independently selected from 0, 1, 2, 3 and 4; and

15.- The ligand according to claim 13, having formula (Ila), (lib) or (lie).

16.- A process for preparing a ligand Lof formula (II) as defined in claim 13, comprisinga reaction between a compound of formula (Illa), or a combination of compounds of formula with a compound of formula (IV)

R¹, R², R³, R⁴, R⁵ and R⁶ are independently selected from linear or branched C1-C5 alkyl, linear or branched C1-C5 halogenated alkyl, linear or branched O-(Ci-C₅)-alkyl, linear or branched N-(Ci-C₅)-alkyl, linear or branched (Ci-C₈)-P^erfl^uorc>alkyl, linear or branched O-(Ci-C₈)-P^erfl^uor°alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl; preferably selected from linear or branched C1-C5 alkyl, linear or branched O-(C C₅)-alkyl, linear or branched O-(Ci-C8)-p^erfluoroalkyl , and substituted or unsubstituted phenyl; more preferably beingt-Bu;

0 < m < 5; 0 < n < 5; n+m > 1 ; p, q, r and s are independently selected from 1 and 2; and u and v are independently selected from 1 , 2, 3 and 4; in the presence of an organic base; preferably selected from pyridine, diisopropylethylamine, 1 -methylimidazole, butyllithium, and triethylaminealone or in combination with catalytic amounts of 4-dimethylaminopyridine; and more preferably being triethylamine.

17.- A process for preparing aldehydes by a hydroformylation reaction, wherein it comprises the reaction of an olefin with a combination of H₂/CO in the presence of a catalyst according to any one of claims 1 to 9.