CA1037961A - Process for the preparation of tetrahydropyran derivatives and chain unsaturated alcohols - Google Patents

Abstract

THE ABSTRACT OF THE DISCLOSURE
Di-alkenyl substituted tetrahydropyrane as well as higher alcohols are produced by reacting a conjugated diene, like butadiene or isoprene with an aldehyde like formaldehyde and acetaldehyde in the presence of a salt or chelate or coordination compound of Pd or Pt in their oxidation state +2 and a ligand of the type YR3 or Y(OR)3, wherein R is a hydrocarbyl group and Y is phosphorus or arsenic. The alcohols contain carbon numbers equal to the double amount present in the diolefin plus the amount present in the aldehyde.
The products can be saturated for instance by introducing hydrogen using the same catalyst. The unsaturated cyclic ethers are useful as chemical inter-mediates and polymerizable monomers, and the hydrogenation products of the cyclic ethers are useful as high-boiling solvents.

Description

~.~3'~
This invention relates to the production of unsaturated cyclic ethers of the type of di-alkenyl substituted tetrahydropyrans, higher alcohols, ln particular Cg-alcohols, as well as other oxygenated compounds from conjugated dienes and aldehydes, and to novel ;;
compositions of matter obtained by this process. ;
According to the present invention di-alkenyl substituted tetrahydropyrans and unsaturated higher alcohols with carbon numbers equal to the double amount of carbon atoms present in the conjugated diolefin plus the amount present in the aldehyde , are produced by a process comprising contacting a conjugated diolefin ``
with an aldehyde in the presence of a salt or chelate or coordination compound of Pd or Pt in their oxidation state +2 and a ligand of the type YR3 or Y(OR)3 wherein Y is phosphorus or arsenic and ~ is an alkyl group with l to 12 carbon atoms or an aryl or arylalkyl group with an equivalent or higher amount of carbon atoms if the ligand is ~ ~-not already present in the coordination compound. I
The conjugated diolefin rontains at least one grouping - C= I - C= ~

in which the residual valencies on the carbon atoms may be satisfied '~
by hydrogen atoms or hydrocarbon residues or other substituents.

The hydrocarbon residues may comprise aliphatic or aromatic groups and theother substituents may be of inorganic nature, such as halogen atoms. Preferred examples of such conjugated diolefins ::

- 2 -~379~
are butadiene, isoprene, and 2,3-dimethyl butadiene, that is diolefins containing two terminal conjugated double bonds.
The aldehydes used in this process are preferably aliphatic aldehydes containing 1 to 12 carbon atoms. They may be substituted with functional groups like for example hydroxyl-groups, formyl groups, acetyl groups or nitrogen containing groups.
They may also carry other heteroatoms like for example halogens.
Aromatic aldehydes may also be used.
Preferred are the lower aliphatic aldehydes and most preferred is formaldehyde.
Also dialdehydes will undergo the reaction with the con~ugated diolefins, such as glyoxal.
Any compound releasing the aldehydes cited above under the reaction ;~ `
conditions may be employed in place of these aldehydes. ;
Salts, chelates or coordination compounds of ,,~,:,;
palladium or platinum with the above mentioned ligands have been `- ;
. .~
found to be effective catalysts for the reaction in question. ;
The salts or chelates can be introduced into the reaction vessel together with the ligand, with the advantage that no preformation of the coordination compound is necessary. The coordination compounds of Pd or Pt in their oxidation state +2 are based as already above mentioned on complexes formed with ligands of the type YR3 or Y(OR)3 whL:h may or may not have other sdditional ILgands.

., .

~ 3 ~

)37~
Representative structures are bis alkyl phosphine as well as bis-aryl phosphine- coordinated Pd and Pt salts.
Preferred are salts, chelates or coordination compounds of palladium.
Any salt is in principle effective but good results are obtained when using palladium acetate, nitrate, chloride or as a chelate acetylacetonate or coordination compounds of the afore mentioned salts with the ligands YR3 or Y~OR)3. These coordination compounds or complexes may have different or additional ligands provided these ligands can be replaced under the reaction conditions by the ligands YR3 or Y(OR)3 and/or by the diolefins which are the reaction partners as indicated above.
Generally the reaction produces as the major product the cyclic ethers, and as the minor product alcohols in amounts varying from less than 1 to more than 20 %. It may be advantageous to have additionally free phosphines present in the reaction mixture, even in the case when coordination compounds are used containing already the phosphines. They exert a stabilizing ., effect on the catalyst system. On the other hand the reaction rates ~ b increase with decreasing ratio of phosphines to Pd or Pt, resulting also in a change Ln the product composition which then contains higher amounts of Cg-alcohols. ~
Thus the ratio of metal to phosphines (and the other ligands described) `
will broadly lie in the range of 2:1 to 1:15. A ratio of 1:1 is advanttgeout as de:cribed above,i increasing the reaction ra.e.

r :
' ' 37g~1 The reaction is preferably carried out in the liquid phase. Particularly the presence of water is advantageous for a smooth reaction, but also other solvents preferably polar solvents which enhance the miscibility of the reaction partners and water improve the process.
The following list of solvents which should not be considered restrictive shows examples of different classes of solvents which have been successfully employed in the process of this invention : methanol, isopropanolJ tetrahydrofuran, benzene, ;-~
dimethylsulfoxide, formamide, dimethylformamide and hexamethyl ~ ;
phosphoramide.
In case water is present emulsifiers may be employed. ~`
In case the anion of the palladium salt is the conjugated base of a strong acid,but not only then,the additional presence of a buffer or base, e.g., sodium acetate or sodium carbonate is useful and may speed up the reaction.
The presence of C02 increases the amount of alcohols in the reaction product.
The concentration in the reaction mixture of the salt or chelate or coordination compound of Pd or Pt metal preferably lies within the range O.OOOl to 0.05 molar, more preferably lies within the range O.OOl to 0.02 molar.
The process according to the invention is carried out at a temperature within the range of 0 to 200 C, preferably within the range o~ 50 to 150 C and more preferab1y uithin the range oi ~ : ' .~ :~: . .. - ..

~ 037~
80 to 110 C. The molar ratio o~ conjugated diene to aldehyde is broadly within the range 1:5 to 11:1.
The process according to the invention leads to p~oducts which are composed of one or more isomers oE six membered cyclic ethers which are doubly substituted with unsaturated side chains. ~-In addition products are formed comprising primary and secondary alcohols with carbon atoms equal to the double amount of carbon atoms present in the conjugated diolefin plus the amount present in the aldehyde.
The process according to the invention can be considered as a simultaneous co-cyclotrimerization and co-trimer-ization of aldehydes with conjugated diolefins. It could not be expected from prior art processes of dimerizing conjugated diolefins that such a combined co-cyclotrimerization and co-trimerization reaction would occur.
The cyclic ethers can be generally represented by the following chemical structure :
~'` ' ' R13 H R8 .-R3 ~ \(2) D
C C--R~ C' C
Rl--C~ 3~/ R10 R9 R2 R5 R6 R12 Rll Type I Isomer : :`

:~

., .:: . . . , :.,-: . , : ,. : - .

~V379~1 wherein the Rl 13 substituents represent hydrogen, alkyl, aryl, substituted alkyl, substituted aryl or halides, like chlorine or other heteroatoms. They may be all equal, for instance hydrogen, or different, for instance hydrogen, ~ethyl and ethyl groups.
The number of carbon atoms of the alkyl substituents may be `~
from 1 to 12, but preferably it is not higher than 4.
A second group of cyclic ethers, Type II isomer, produced usually in a ratio of about 1:2 to 1:3 are isomers of the Type I cyclic ethers~ which carry the alkylidene substituents -on the carbon atoms C2 and C4 instead of C2 and C5.
It will be understood that the reaction is easier to perform the less substituents are present. The ether structure will of course be dependent on the type of substituents present in the starting materials. If butadiene and formaldehyde are reacted according to the process of the invention all the substituents are hydrogen, the formula for the Type I isomer is then H H H

H~ C--\ D--H ~:
C C--H C, C
/ H

H -C~ H ~ H H H

.` ' '~:
, .', .-- ~ .. . .; , : , ~037a~
Similarly Lf isoprene and formaldehyde are reacted according to the process of the invention the structure, in which R3 and R9 are equal to CH3 and the other R'srepresent hydrogen, is as follows for the Type I isomer.

. H H H
CH~~C--O~ C H
CC--H C C
D \ / H CH 3 H C~ &\ ~
H H H H H ~ .

Isomeric structures here also exist wherein R4 and Rlo or R4 and R
.or R3 and Rlo are methyl groups. Also stereoisomers are possible.
If acetaldehyde is one of the reactants the above~structures will possess a methyl group represented by R13.
The same structures apply to the Type II isomer with the alkylidene substituents in the 2,4 position.
-If the dialdehyde glyoxal is one of the reactants and butadiene the other the following trifunctional cyclic ether and its Type II isomer are the products, which are new compositions of matter. CH-O H

H C--G C- - H
\c- c/~ \c--cD ;~ ~
H ~ C~ ~C, ,'~`
H H H h H

: .
:

. - .; . . . .. .
`/` . : . . . , . ` . ` ` ,: ` ~ . ` . ` . -~0379~
' , :~
The unsaturated cyclic ethers are useful as chemical intermediates and polymerizable monomers.
The unsaturated cyclic ethers as represented by the above formulae can be subjected to mild hydrogenation using suitable catalyst systems, such as for instance the cat~lyst system which catalyses the present reaction. A convenient way to carry out such a process is by performing the present reaction for a time sufficient to produce the cyclic ethers and then introducing hydrogen in the reaction vessel.
The saturated cyclic ethers, which are novel compounds can be represented by a similar structural formula as the unsaturated ones, namely . :
Rl3 H R8 ` `-\ / \
'` \ / \ / ';;-, H C--R4 C` C :
H/ \ / RlO
Rl--C\ C & R9 - R2 R5 R6 R12 Rll - ~:
. . .

- wherein the R substituents have the same meaning as above.
Corresponding formulae can be designated to the saturated cyclic - ethers derived from butadiene and formaldehyde, isoprene and - formaldehyde and butadiene or isoprene and acetaldehyde. ~;
Similar compounds ~re formed fr Type II isomers. Such saturated cyclic ethers can be used as high boiling solvents. ~-~

~ ,:
~ _ 9 _ ' ,'' '' ~ 37~
The unsaturated cyclic ethers can be oxidized to diepoxides and diacids, wherein the epoxide groups and acid groups are attachcd to the pyrane ring, which may be substituted.
They can also be converted to dialcohols by hydroformylation, the alcohol groups becoming attached to the side chains. High temperature hydrogenation will lead to ring opening to give among others primary branched alcohols of the 2-ethyl heptanol type, which are useful as plasticizer alcohols.
In the process of the invention also primary and secondary unsaturated alcohols are produced in addition to the cyclic ethers.
The general structure of these novel alcohols which can be obtained by the process according to the invention ~ can be represented by the following formulas R~
.~ R~ ~H-OH R R
~C C~R C - - C

R R R R R

: R CH-OH R R
C C--R R--C --C
~C~ C R
R R R R R R R

~7~

R CH-OH 1~ R
C--C--R C=C

R~C~ R/\R R/\R R/~

wherein the R's substituents represent hydrogen, alkyl, aryl, - substituted alkyl, substituted aryl or halides, like chlorine or : ?~
other hetero atoms. They need not be equal.
More specifically in case the terminal carbon ;~
: atoms of the conjugated diolefins have only hydrogen the :
structures are as follows :
R
.. R~ ~H-OH R R ; ~ `

/ \H~ C--H :

~C~ H
. H H H H H H H ~`:H .:

- 11 - ~.
.-, . ~:

~Q37~

R~
R CH-OH F~ R
C C--R C=C
~C~ &\ / \ ~ \ H .;::
H H H H H H H H

- In case butadiene and formaldehyde are the reactants the following three unsaturated primary alcohols which on hydrogenation give all 2-ethyl heptanol, a potential plasticizer alcohol, are formed besides the cyclic ethers.

J~ ~H2-OH H H

~C~ ~C~ ~C ~--H
H H H H H H

H CH2~H H~

~c~/ ~c~cf ~ H
i I H H H H H H ~ ~ :

.. ; , , ~''.
'' ' ''' ~':

~379 H CH2~H H H
~C - C~H f - C 2-vinyl-5-heptenol ~C~ H
~ I H H tl H H t I H
The ethers and alcohols produced accor.ding to the process of the invention can be isolated by means of gas-liquid chromatography or distillation.

.
EXAMPLE 1 :
2.1 g (3 mmol) bis-triphenylphosphine palladium dichloride, 2.4 g (9.15 mmoles) triphenylphosphine, 0.508 g (6 mmoles) sodium-acetate and 110 g of 35 % solution of formal-dehyde (1.29 moles) in water were placed into an autoclave and ]50 g (2.78 moles) butadiene added thereafter. The mixture was heavily stirred and kept at 85 C for 20 h. After cooling to room temperature the unreacted butadiene was vented.
The reaction product separated in two phases. 132 g (88 %) of the originally charged butadiene was converted to organic products. The organic layer weight was 180 g, the weight of ;
the water layer was 60 g. -~
- By G.L.C. it was shown that 40 % of the organic layer consisted of two compounds (ratio about 2:1) which were - shown by Nuclear Magnetic Resonance to be 2.5-divinyltetrahydropyran [(multiplets centered around S 5.6 and ~ 5 (2 vinyl groups) as well ~ `:
' _ 13 --`

- -; : - .` . , - . .

~037~
as around ~3.8 and b 3.1 (3 protons in~ position to oxygen~
a slightly broad peak at c~2.1 (CH-C=C proton)and a multiplet between ~ 1.9 (two CH2 groups~ and 2.4-divinyltetrahydro-pyran ~multiplet centered around ~ 5.6 and ~5 (2 vinyl groups) as well as around ~3.6 (3 protons in~< position to o~ygen);
a slightly broad peak centered at ~2.:L (CH-C=C proton) and a multiplet between ~ 1.4 - 1.7 (two CH2 groups)~ .
Infrared spectrum and mass spectrum of both compounds were identical. (Parent peak at m/e 138, base peak at m/e 54).
6 % of the organic layer was proved to consist of doubly and triply unsaturated Cg alcohols of the following structure.

A) 2 1 2 2 2 2 NMR : A multiplet between ~ 4.8 - ~6.1 ppm (two vinyl groups); doublet at ~ 3.3 (CH2-0 grouping); OH protons which shifts on dilution; broad three proton multiplet, centered at ~2.1 (=C-CH2 and =C-CH-); multiplet ~ -- between Sl.l and S 1.6 is due to the two remaining methylene groups. ~

Mass Spectrometry : No parent peak but diagnostic `
peaks at m/e 122 (P-18); m/e 125 (P-15); m/e 109 (P-31); m/e 107 (P-33).

.` - '.
B) CH2 = CH - CH - CH2 - CH2 - CH = CH - C~1 CH OH

, ' ~' ' :

, ' ~", ~.

':

' `' .

NMR : Multiplet betw~en ~4.8 - S6.1 (vlnyl group) and multiplet cencered around SS.4 (internal double bond protons). Doublet at S3.3 (CH2-0 grouping~. Methyl on double bond (doublet at Sl.6). Broad three protons multiplet centered at $2.1 (CH2-C= and =C-CH-). Multiplet between ~1.2 and ~ L.5 represents the remaining methylene group. 0~ peak shifts on dilution.
Mass Spectrometry : The mass spectrum Is identical with that of the above Cg isomer.

. .
C) CH2 = CH - IH - CH2 - CH = CH - CH = CH

::
NMR : Wide range of absorptions between S4.8 - ~6.7 (8 protons) indicate conjugated double bonds.
The doublet at S3.4 is due to the methylene group adjacent to oxygen, The broad absorption between ~ 2 and S 2.5 is due to the =C-CH2 and =C-CH groupings.
The OH peak shifts on dilution. ~-~
:
Mass Spectrometry : No parent peak but diagnostic peaks at m/e 120 (P-18); m/e 107 (P-31) and m/e 105 (P-83).

0.68 g (3 mmoles) palladium acetate, 1.82 g (9 mmoles) ~ -~
tri-n-butylphosphine, 85 g of a 35 % solution of formaldehyde (1 mole) in water were placed into an autoclave and 334 g (6.2 moles) butadiene added thereafter.

:' ,.

~, ~

:~V;~79~
The mixture was heavily stirred and kept at 35 C
for 3 hours. After cooling and venting the unreacted butadiene, 223 g of a greenish-yellow organic phase was separated from the two phase reaction product. Flash distillation under reduced pressure gave 211 g of organic product, which was found to contain 48.7 %
of a mixture of 2.5- and 2.4-divinyl-tetrahydropyran and 20 % of 1.3.7 -octatriene along with less than 1 % of C9-alcohols.

- ' EXAMPLE 3 :
0.17 g (0.75 mmoles) palladium acetate, 0.20 g (0.75 mmoles) triphenylphosphine, 42.5 g of a 35 /0 solution of formaldehyde in water (0.5 moles~ and 162 g (3 moles) of butadiene ~ -were charged to an autoclave and heated to 85 C under heavy stirring for 40 minutes.
The 66.8 g of organic product were shown to contain in addition to some by-products 13.7 % 1.3.7-octatriene, ~-34.2 % divinyltetrahydropyrans and 25.1 % unsaturated C9-alcohols.
, EXoMPLE 4 :
0.23 g (0.75 mmoles) palladium acetylacetonate, 0.20 g (0.75 mmoles) triphenylphosphine, 42.5 g of a 35 % solution of formaldehyde in water (0.5 moles) and 165 g (3.05 moles) of butadiene were charged to an autoclave and heated under heavy - stirring to 85 C for 1 hour. The organic layer of the reaction product was analysed by GLC and found to contain, besides some -other unidentified products, 10.7 % 1.3.7-octatriene, ~
"' ; ':' `',' . . . . .. . . . .. - .. ,.. ,, ,.. . .:- . . .,-.. ... -: ; - :
.. :- . . . ... . .

iV379~
33.9 % divinyl-tetra~ydropyrans and 21.6 ~/~ unsaturated Cg-alcohols. ;~

EXAMPLE 5:
0.34 g (1.5 mmoles) palladium acetate, 4.6 gj;
(14.7 nnnoles) triphenylarsine, 42.5 g of a 35 % water solution o~-formaldehyde (0.5 mole) and 172 g (3.18 moles) of butadiene were charged to an autoclave and heated to 85 C under heavy stirring for

3 hours.
22.5 g of organic product were obtained. Its com-position after flash distillation was shown to be, besides some side ;' products, 5.2 % octatriene, 28 % divinyl tetrahydropyrans and 42 %
Cg alcohols.

EXAMPLE 6:
2.37 g (3 mmoles) PtC12 (PPh3)2, 2.4 g (9 mmoles)triphenylphosphine, 2.54 g (18.5 mmoles) sodiumacetate-hydrate, 85.5 g of a solution of formaldehyde (1 mole) in water and 324 g (6 moles) butadiene were charged to an autoclave and heated to 85 C under heavy stirring for 3 hours. Then 10 g organic product could be separated from the unreacted formaldehyde-water layer.
GLC analysis showed that this product contained besides some other unidentified products the following compounds: 6.8 ~O
octatriene, 56.4 % divinyl tetrahydropyrans and 2 % unsaturated Cg-alcohols.
::

,:
- 17 - ~
~ ' ~
, EX~`~LE 7 ~ 7~
The butadiene of Example 1 was replaced by 280 ml (180 g, 2.8 moles) isoprene, all other conditions belng the same.
A mixture of four isomers of the expected cyclic ether, namely 2.5-diisopropenyltetrahydropyran, 2-isopropenyl-5-vinyl-5-methyl tetrahydropyran, 5-isopropenyl-2-vinyl-2-methyl-tetrahydropyran, and 2.5-divinyl-2.5-dimethyltetrahydropyran was formed as the major product as was shown by mass-spectrometry and nuclear magnetic resonance. Similar type II isomers are also present in minor amounts.

.- :

EXAMPLE 8 :
2.1 g (3 mmoles) bis-triphenyl phosphine palladium-dichloride, 2.4 g (9.15 mmoles) triphenyl phosphine, 0.508 (6 mmoles) sodium acetate, 60 ml of degased watar, and 65.5 g acetaldehyde (1.5 moles) were placed into an autoclave and 138 g (2.56 moles) butadiene added thereafter. After 20 h at 85 C a weight increuse from reacted butadiene of 24.4 g (17.5 %) was found. 9.6 % of the organic layer (weighing 57.3 g) was shown by mass-spectroscopy, to be 2.5 divinyl-6-methyl tetrahydropyran 0.34 g (1.5 mmoles) palladium acetate, 1.57 g (6 mmoles) triphenylphosphine, 36.2 g glyoxal (40 % solution in . . .
water, 250 mmoles) and 162 g (3 moles) butadiene were charged to an autoclave and heated for 1 hour and 50 minutes under heavy stirring to 85 C.

:- -~ 7~
The crude reaction product contained 70 g of ratherviscous organic material. It was shown by GLC analysis and by NMR
spectroscopy to consist among others of 1.3.7-octatriene, 2.7~

octadienol and 6-formyl-2.5-divinyl-tetrahydropyran `~

C/H \C~
H - -- C ~
H H H H H - -NMR : Doublet at S 9.2 (aldehyde proton); multiplets - centered around ~5 and S5.6 (2 vinyl groups) and ~' multiplet between S3.4 and 54 (protonsin ~ position ~ ~ ~
to oxygen). ~lultiplet between ~ 1.2 and ~ 2.3 is due ~ , to CH~ CH2 groups-Mass Spectrometry : Parent peak is at m/e 166, .~ .
base peak at m/e 54. The important fragment at m/e 137 is formed by loss of CH0 group.
i. ~
EXAMPLE 10 : ~ -In an experiment which otherwise was carried out ~ -exactly in the same way as example 1 after 20 h of reaction time the unreacted butadiene was vented after cooling to room temperature.~
Then 102 atm. of hydrogen were pressed in the reactor, 57 atm of which were absorbed within 150 min.
, . i ~ , Calculated on butadiene charged a yield of 67 %
of a virtually completely saturated oxygenated hydrocarbon mixture was obtained.
The products which were separated represented the hydrogenation products of the compounds obtained in Example 1.

- 19~

~Q379~
~- By GLC, mass-spectrometry~ nuelear magnetie resonance most of the prod-let was shown to be 2.5 and 2.4 diethyltetrahydropyran. `~
It was aeeompanied by saturated Cg aleohols. :
. ` '.;,, .
'~ ' ~, ~
- 2 ~ ~
.::
:

- ~ .
.` .~, ~
..,,,`,.".,., ~.....

i;,,.-. . .:

. . .~ `
:,`. :

: ` ', ".' . ~, - "~

:' 'j ~ ~ -, "`''~ :

.. ,'~ ~: '

Claims (34)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the production of di-alkenyl substituted tetra-hydropyrans and unsaturated alcohols containing carbon numbers equal to the double amount of carbon atoms present in the diolefin reactant plus the amount present in the aldehyde reactant, comprising contacting a conjugated diolefin with an aldehyde at a temperature of between 0 and 200°C in the presence of a salt or chelate or coordination compound of Pd or Pt in their oxidation state +2 and a ligand of the type YR3 or Y(OR)3 wherein Y is phosphorus or arsenic and R is an alkyl group with 1 or 12 carbon atoms or an aryl or arylalkyl group with an equivalent or higher number of carbon atoms, if the ligand is not already present in the coordination compound.

2. A process according to Claim 1, wherein the conjugated diolefin is butadiene.

3. A process according to Claim 1, wherein the conjugated diolefin is isoprene.

4. A process according to Claims 1 to 3, wherein aliphatic alde-hydes are used containing 1 - 12 carbon atoms.

5. A process according to Claims 1 to 3, wherein formaldehyde is used.

6. A process according to Claims 1 to 3, wherein acetaldehyde is used.

7. A process according to Claims 1 to 3, wherein glyoxal is used.

8. A process according to Claims 1 to 3, wherein the concentration of the Pd or Pt salt, chelate or coordination compound is in the range of 0.0001 to 0.05 molar.

9. A process according to Claims l to 3, wherein the concentration of the Pd or Pt salt, chelate or coordination compound is in the range of 0.001 to 0.02 molar.

10. A process according to Claims 1 to 3, wherein the reaction temperature is within the range of 50 - 150°C.

11. A process according to Claims 1 to 3, wherein the molar ratio of the conjugated diolefin to the aldehyde is within the range of 1:5 to 11:1.

12. A process according to Claims 1 to 3, wherein Palladium acetyl-acetonate is used.

13. A process according to Claims 1 to 3, wherein a nitrate, a chloride or acetate of palladium is used.

14. A process according to Claim 2, wherein the coordination compound which is used is Pd(II) or Pt(II) with YR3 ligands, wherein Y is phosphorus.

15. A process according to Claim 14, wherein the coordination compound which is used is Pd(II) or Pt(II) with triphenylphosphine or tri-n-butyl phosphine.

16. A process according to Claims 1 to 3, wherein the ratio of the metal to phosphines is from 2:1 to 1:15.

17. A process according to Claims 1 to 3, wherein the ratio of the metal to phosphines is 1:1.

18. A process according to Claims 1 to 3, wherein sodium acetate or sodium carbonate is present as a buffer.

19. A process for preparing saturated substituted tetrahydropyrans as well as saturated alcohols, wherein unsaturated tetrahydropyrans are pre-pared according to one of the processes claimed in Claims 1 to 3 and then introducing hydrogen in the reaction vessel.

20. Unsaturated alcohols of the following structures:

wherein the R's (which need not be equal) represent hydrogen, alkyl, aryl, or halide radicals.

21. Unsaturated alcohols as claimed in Claim 20, with the following structure:

wherein the R's (which need not be equal) represent hydrogen, alkyl, aryl, or halides.

22. 2-Vinyl-6-heptenol.

23. 2-Vinyl-5-heptenol.

24. 2-Vinyl-4.6-heptadiene-ol.

25. A process according to any one of Claims 1 to 3 wherein the reaction is carried in the presence of water or a polar solvent.

26. A process according to any one of Claims 1 to 3 wherein the process is carried out in the presence of carbon dioxide.

27. A process according to any one of Claims 1 to 3 wherein the reaction temperature is between 80° and 110°C.

28. A process for producing tetrahydropyran compounds from the elements of an aldehyde having from 1 to 3 carbon atoms and 2 molecules of an olefinic hydrocarbon having two conjugated ethylenic linkages and having from 4 to 8 carbon atoms, which comprises reacting in the liquid phase said aldehyde and said olefinic hydrocarbon in the presence of a catalytic amount of a palladium compound complexed with a trihydrocarbyl phosphine at a temperature of about 40°C to about 150°C.

29. A process for producing tetrahydropyran compounds from the elements of formaldehyde and two molecules of an olefinic hydrocarbon having two conjugated ethylenic linkages and having from 4 to 8 carbon atoms, which comprises reacting in the liquid phase formaldehyde and said olefinic hydro-carbon in the presence of a catalytic amount of a zero-valent palladium compound represented by the formula (R' 3P)3Pd or (R' 3P)4Pd wherein R' independently is a hydrocarbyl group of from 1 to 20 carbon atoms selected from saturated aliphatic, saturated cycloaliphatic and mononuclear aromatic, at a temperature of from about 40°C. to about 150°C.

30. The process of Claim 29 wherein the molar ratio of olefinic hydrocarbon to formaldehyde is from 5:1 to about 1:5 and the amount of palladium compound is from about 0.1%wt. to about 10%wt. based on diolefin.

31. The process of Claim 30 wherein at least one of the conjugated ethylenic linkages is terminal.

32. The process of Claim 31 wherein R' is mononuclear aromatic.

33. The process of Claim 32 wherein the palladium compound is tetrakis (triphenylphosphine) palladium.

34. The process of Claim 33 wherein the olefinic hydrocarbon is butadiene.