PRODUCTION OF OPTICALLY ACTIVE ALPHA-IONONE

Japanese Patent JP3756266

B2

PROBLEM TO BE SOLVED: To profitably obtain the subject compound useful as a raw material for compounded perfumes by bringing optically active 3-(2,6,6-trimethyl-2- cyclohexen-1-yl)-acrylonitrile into contact with methyl lithium. SOLUTION: This method for producing optically active α-ionone of formula V comprises treating racemic 2,4,4-trimethyl-2-cyclohexene-1-ol compound of formula I [R is H, a group of the formula: COR\' (R\' is a 1-10C alkyl which may be substituted with a halogen, an alkenyl)] with a lipase originated from Penicillium chrysogenum, reacting the obtained optically active compound of formula II [the wavy line expresses (R)-isomer or (S)-isomer] with an alkylvinylether in the presence of pivalic acid, reacting the optically active aldehyde of formula III with KCN in the presence of acetic acid, dehydrating the reaction product, and subsequently bringing the obtained optically active 3-(2,6,6-trimethyl-2-cyclohexen-1-yl)acrylonitrile of formula IV into contact with methyl lithium.