RU2313534C1 - Method for preparing 1,3-bis-(diethylphosphinomethyl)-benzene (variants) - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of 1,3-bis-(diethylphosphinomethyl)-benzene of the formula:

Invention proposes two methods of synthesis. By the first method diethylphosphine is subjected for interaction with 1,3-bis-(dibromomethyl)-benzene and formed phosphonium salt is treated with potassium carbonate. By the second method diethylphosphine borane complex is subjected for interaction with 1,3-bis-(dibromomethyl)-benzene in mixture of toluene and alkali aqueous solution followed by treatment of formed 1,3-bis-(diethylphosphinomethyl)-benzene borane complex with fluoboric acid dimethyletherate and sodium hydrocarbonate solution. Compound can be used as a ligand for homogenous catalysts in hydrogenation, cross-linking, polymerization and carbonylation reactions. Proposed methods for synthesis of the end substance are simple in realization and don't require using components combustible in contact with air and complex procedures.

EFFECT: improved method of synthesis.

2 cl, 2 ex

Description

FIELD OF THE INVENTION

The invention relates to organic chemistry, in particular to compounds that can be used as a ligand for homogeneous catalysts in the reactions of hydrogenation, dehydrogenation, cross-coupling, polymerization and carbonylation, and production methods.

State of the art

Derivatives of 1,3-bis (phosphinomethyl) benzene are widely used in the synthesis of effective homogeneous pincer type catalysts based on palladium, ruthenium, rhodium, platinum, iridium, osmium, etc. [Milko E. van der Boom, David Milstein Chem. Rev. 2003, 103, 1759-1792]

A compound with a different arrangement of diethylphosphinomethyl substituents is known - 1,2-bis (diethylphosphinomethyl) benzene [J.W. Raebiger, A.Miedaner, C.J. Curtis, S.M. Miller, O. P. Anderson, D. L. DuBois J. Am. Chem. Soc. 2004, 126, 5502-5514].

However, this compound cannot be used as a ligand for pincer type catalysts due to its structure.

1,3-bis (diethylphosphinomethyl) benzene can be used as a ligand for homogeneous catalysts, which has high donation and small spatial difficulties in the reactions of hydrogenation, dehydrogenation, cross-coupling, polymerization and carbonylation.

A known method of producing derivatives of 1,3-bis (phosphinomethyl) benzene by reacting metal phosphide (R ₂ PM) with 1,3-bis (halogenmethyl) benzene [C. J. Moulton, B. L. Shaw, J. Chem. Soc., Dalton Trans. 1976, 1020-1024].

The method is not suitable for the synthesis of 1,3-bis (diethylphosphinomethyl) benzene due to the formation of a large number of inseparable by-products.

A known method of producing derivatives of 1,3-bis (phosphinomethyl) benzene by the interaction of 1,3-bis (methylmagnesium) benzene with halogen phosphine [P. A. Chase, M. Gagliardo, M. Lutz, ALSpek, G. R. M. van Klink, G. van Koten Organometallics 2005, 24, 2016-2019]. R = C ₆ F ₅

The method is technically complicated due to the preparation of the bifunctional Grignard reagent, is ineffective (product yield does not exceed 51%) and requires the use of a large amount of solvent.

A known method of producing derivatives of 1,3-bis (phosphinomethyl) benzene by reacting phosphine (R ₂ PH, R = t-Bu, Cy) with 1,3-bis (bromomethyl) benzene [Gusev, DG; Madott, M .; Dolgushin, F.M .; Lyssenko, K.A .; Antipin, M.Y. Organometallics 2000, 19, 1734 .; H.Lebel, S. Morin, V. Paquet Org. Lett. 2003, 5 (13), 2347-2349, E. Hollink, JC Stewart, P. Wei, DW Stephan, Dalton Trans., 2003, 3968-3974].

The method cannot directly be used to produce 1,3-bis (diethylphosphinomethyl) benzene, since triethylamine (EtaN) does not destroy the phosphonium salt of 1,3-bis (diethylphosphinomethyl) benzene.

A known method of producing derivatives of 1,3-bis (phosphinomethyl) benzene by reacting a borane complex of phosphine with 1,3-bis (bromomethyl) benzene [H.Lebel, S. Morin, V. Paquet Org. Lett. 2003, 5 (13), 2347-2349] in a mixture of toluene and an aqueous solution of alkali.

1,3-bis (diethylphosphinomethyl) benzene has not yet been obtained by this method.

Disclosure of invention

The problem solved by the claimed inventions is to create a technically simple method for producing 1,3-bis (diethylphosphinomethyl) benzene, feasible at room temperature or with slight heating.

As a result of the studies, two new methods have been created that allow efficient production of 1,3-bis (diethylphosphinomethyl) benzene. (The yield is 50% -83%.)

The first production method is characterized in that diethylphosphine is reacted with 1,3-bis (dibromomethyl) benzene, and the resulting phosphonium salt is treated with potassium carbonate. This method allows to obtain 1,3-bis (diethylphosphinomethyl) benzene with a yield of 50% in pure form by distillation in vacuo and is designed to produce multi-gram quantities of the product.

The second method is characterized in that the borane complex of diethylphosphine is reacted with 1,3-bis (dibromomethyl) benzene in a mixture of toluene and an aqueous solution of alkali, then the resulting borane complex of 1,3-bis (diethylphosphinomethyl) benzene is treated with borofluoride acid dimethyl ether and sodium bicarbonate solution . This method allows you to effectively obtain gram quantities of 1,3-bis (diethylphosphinomethyl) benzene with a yield of 83%. This method is simple to implement, does not require the use of flammable components in contact with air and complex procedures.

The implementation of the invention

The interaction of diethylphosphine (Et ₂ PH) with 1,3-bis (bromomethyl) benzene is carried out in accordance with the following reaction:

The yield of 1,3-bis (diethylphosphinomethyl) benzene in two stages is 50%.

The interaction of the borane complex of diethylphosphine (Et ₂ RNBH ₃ ) with 1,3-bis (bromomethyl) benzene is carried out in a mixture of toluene and an aqueous solution of alkali with a yield of 90%. The resulting borane complex of 1,3-bis (diethylphosphinomethyl) benzene is treated with borofluoride acid dimethyl ether (HBF ₄ Me ₂ O) and potassium carbonate solution. The yield of the target product is 83% in two stages.

The method is illustrated by the following examples.

EXAMPLE 1

Stage 1

To a mixture of diethylphosphine borane complex (Et ₂ RNBH ₃ ), 5.2 g (50 mmol) of tetra-butylammonium chloride (Bu ₄ NCl) 1 g (3.2 mmol), 150 ml of toluene and 120 ml of 30% KOH, 5.28 g of 1,3- bis (dibromomethyl) benzene (20 mmol) in 50 ml of toluene. Stirred for 3 hours at room temperature. The organic layer was separated, washed with water and a saturated solution of sodium chloride (NaCl), the aqueous fraction was extracted with ether (Et ₂ O), the combined fractions were dried over magnesium sulfate (MgSO ₄ ). The solvent was evaporated and the residue was purified by chromatography on silica gel (2% ethyl acetate / hexane). Received borane complex of 1,3-bis (diethylphosphinomethyl) benzene, 6.2 g (90%), colorless crystals. NMR ³¹ P- { ¹ H} δ 22.25 ppm (CDCl ₃ ); NMR ¹ H (CDCl ₃ ): 1.09 d.t. (12H), 1.54 m. (8H), 4.10 d. (4H), 7.03 m. (3H), 7.22 m. (1H).

Stage 2

Borane complex 6 g was dissolved in 60 ml of methylene chloride (CH ₂ Cl ₂ ) in an argon atmosphere and 4 equiv. borofluoride acid dimethyl ether (HBF ₄ Me ₂ O) at -5 ° C. It was stirred for 24 hours at room temperature, an excess of saturated sodium bicarbonate solution (NaHCO ₃ ) was added at 0 ° C, and stirred for 4 hours at room temperature. The organic layer was separated and washed with saturated NaCl. 5.03 g (92%) of 1,3-bis (diethylphosphinomethyl) benzene (colorless oil) were obtained. NMR ³¹ P- { ¹ H} δ - 15.07 ppm. (C ₆ D ₆ ); ¹ H NMR (CDCl ₃ ): 1.08 d.t. (12H), 1.41 m. (8H), 2.78 s. (4H), 7.02 m. (3H), 7.21 m. (1H).

EXAMPLE 2

1,3-bis (dibromomethyl) benzene 5.71 g (21.6 mmol) was placed in a 100 ml flask and methanol 50 ml was added, the flask was purged with argon and Et ₂ PH 4.3 g (47.4 mmol) was added with a syringe at 20 ° С . It was mixed for 12 hours and the solvent was distilled off in vacuo while heating in a water bath. To the residue was added 70 ml of absolute methylene chloride and 12 g of potassium carbonate was stirred for 24 hours under argon atmosphere. The organic layer was separated and evaporated in vacuo. After distillation, 3.04 g (yield 50%) of 1,3-bis (diethylphosphinomethyl) benzene was obtained as a colorless oil, T _{boiling point} 110 ° С (0.05 mm).

Industrial applicability

1,3-bis (diethylphosphinomethyl) benzene can be used in the preparation of homogeneous cross-coupling catalysts, hydrogenation, dehydrogenation, in carbonylation reactions, polymerization of olefins, etc. The proposed methods for producing a new valuable component for catalysts are technological and cheap and can be carried out in industrial conditions.

Claims (2)

1. A method for producing 1,3-bis (diethylphosphinomethyl) benzene, characterized in that diethylphosphine is reacted with 1,3-bis (dibromomethyl) benzene, and the resulting phosphonium salt is treated with potassium carbonate. 2. A method of producing 1,3-bis (diethylphosphinomethyl) benzene, characterized in that the borane complex of diethylphosphine is reacted with 1,3-bis (dibromomethyl) benzene in a mixture of toluene and an aqueous alkali solution, then the resulting 1,3-bis borane complex (diethylphosphinomethyl) benzene is treated with borofluoride acid dimethyl ether and sodium bicarbonate solution.