Regio-and Stereoselectivity of Peracid Oxidation of 20-Hydroxy-2,3:20,22-di-O-isopropylidene-7,8-dihydroecdysone

摘要

Oxidation of 7,8-dihydro analogs of ecdysteroids with peroxy acids(Baeyer-Villiger reaction)provides a method for the transformation of the steroid B ring into seven-membered lactone ring typical of brassino-lide(plant growth and development hormone isolated from the Brassica napus rape pollen)[1].The reaction of 7,8-dihydro-20-hydroxyecdysone 2 beta,3 beta:20,22-di-acetonide(I)[2]with m-chloroperoxybenzoic acid in methylene chloride gave 20-hydroxy-7,8 alpha-dihydro-5a-oxa-5a-homoecdysone 2 beta,3 beta:20,22-diacetonide(II)with high regio-and stereoselectivity.