Preparation of cis—olefins
AssigneesNissan Chemical Industries, Ltd., Fumie Sato
InventorsFumie Sato, Katsuaki Miyaji, Takehiro Amano
Life of this patent
Estimating the term…
Abstract
A cis-olefin of the formula: R1—CH═CH—R2 is prepared by reducing an alkyne of the formula: R1—C≡C—R2 with formic acid in the presence of a palladium catalyst. R1 and R2 are independently selected from the group consisting of a hydrogen atom, ester group, substituted silyl group, carboxyl group, cyano group, aliphatic C1-C20 hydrocarbon group, and phenyl group. The cis-olefin which is a useful intermediate for the synthesis of fine chemicals is selectively produced in high yields.
Claims7
A method for preparing a cis-olefin of the following general formula (2):
- wherein R1 and R2 are independently selected from the group consisting of (1) an ester group, (2) substituted silyl group, (3) carboxyl group, (4) cyano group, (5) aliphatic hydrocarbon group having 1 to 20 carbon atoms unsubstituted or substituted with at least one ester group or unprotected or protected hydroxy group with at least one substituted silyl group, alkoxyalkyl group, acyl group, trityl group, tetrahydropyranyl group, benzyl group or p-chlorobenzyl group, and (6) phenyl group unsubstituted or substituted with at least one hydroxy group, with a proviso that R1 and R2 are not simultaneously unsubstituted aliphatic hydrocarbon groups or phenyl groups, said method comprising the steps of
- forming a mixture comprising formic acid, triethylamine, n-tributylphosphine, and tris(dibenzylideneacetone) dipalladium (0)-chloroform adduct (Pd2(DBA)3CHCl3) in a solvent, and subsequently
- adding thereto an alkyne of the following general formula (1):
- R1—C≡C—R2 (1)
- wherein R1 and R2 are as defined above, under effective reduction conditions,
- wherein said formic acid is present in said mixture in a molar amount greater than the molar amount of the alkyne up to about 1000 mol % based on the amount of the alkyne and the palladium complex catalyst is present in an amount of about 0.1 to 100 mol % based on the amount of the alkyne.
A method for preparing a cis-olefin of the following general formula (2):
- wherein R1 and R2 are independently selected from the group consisting of (1) an ester group, (2) substituted silyl group, (3) carboxyl group, (4) cyano group, (5) aliphatic hydrocarbon group having 1 to 20 carbon atoms unsubstituted or substituted with at least one ester group or unprotected or protected hydroxy group with at least one substituted silyl group, alkoxyalkyl group, acyl group, trityl group, tetrahydropyranyl group, benzyl group or p-chlorobenzyl group, and (6) phenyl group unsubstituted or substituted with at least one hydroxy group, with a proviso that R1 and R2 are not simultaneously unsubstituted aliphatic hydrocarbon groups or phenyl groups, said method comprising the steps of
- forming a mixture comprising formic acid, triethylamine, n-tributylphosphine, and tris(dibenzylideneacetone) dipalladium (0)-chloroform adduct (Pd2(DBA)3CHCl3) in a solvent, and subsequently
- adding thereto an alkyne of the following general formula (1):
- R1—C≡C—R2 (1)
- wherein R1 and R2 are as defined above, under effective reduction conditions,
- wherein said formic acid is present in said mixture in a molar amount greater than the molar amount of the alkyne based on the amount of the alkyne and the palladium complex catalyst is present in an amount of about 0.1 to 100 mol % based on the amount of the alkyne.
Dependencies are inferred from the claim text.