PRODUCTION OF (3,5-DIHYDROXY-2-METHYLENECYCLOHEXYLIDENE) ACETIC ACID ESTERS

摘要

PURPOSE:To easily produce the subject compound on an industrial scale in high yield at a low cost by using 5,7-dihydroxy-8-nonen-2-ynoic acids which are novel compounds derived from an easily and industrially available starting raw material and cyclizing the acids in the presence of a palladium compound. CONSTITUTION:The objective compound of formula n useful as a synthetic intermediate for 1 alpha-hydroxyvitamin D can be produced by cyclizing novel 5,7-dihydroxy-8-nonen-2-ynoic acids of formula I [R<1> and R<2> are tri(1-7C) hydrocarbon-silyl, 1-7C hydrocarbonsilyl or form acetal bond together with O of OH: R<3> is H or 1-4C alkyl] at 0-100 deg.C for 10min to 100hr in a solvent (e.g. benzene) in the presence of a palladium compound such as palladium(II) compound derived from bis(triphenylphosphine)-palladium(II) acetate and triphenylphosphine, etc.