Patent ID: 6495725
Filing Date: 2002-12-17
Classification: C07D,Y02P

Abstract:
A process for the preparation of an optically active enone represented by the formula (4) wherein R2 and R3 jointly represent acetonide, methyl ethyl ketal or diethyl ketal, and R5 represents a hydrogen atom, an alkyl group having not more than 20 carbon atoms or a phenyl group, which comprises steps ofA) deprotecting the protecting group for the hydroxyl group at the 1-position in an optically active compound represented by the formula (1) â€ƒwherein R1 and R4 independently represent a cumyl group, &agr;,&agr;-diethylbenzyl, &agr;,&agr;-dimethyl-p-methoxybenzyl, t-butyldimethylsilyl, trimethylsilyl, triethylsilyl, triisopropylsilyl, isopropyldimethylsilyl or ethyldimethylsilyl, and R2, R3 and R5 are as defined above to form an optically active compound represented by the formula (2) â€ƒwherein R2, R3, R4 and R5 are as defined above, B) oxidizing the hydroxyl group at the 1-position in the compound (2) to form an optically active compound represented by the formula (3) â€ƒwherein R2, R3, R4 and R5 are as defined above, and C) deprotecting the protecting group for the hydroxyl group at the 4-position in the compound (3) to form a double bond between the carbon atom at the 4-position and the carbon atom at the 5-position.