Z-Isomers of Steroid 17β-Side Chain Methyl Acrylates

Abstract

THP-Protected androstan-3-ol 17β-carboxaldehydes I-III with 3β,5-ene, 3β,5α, and 3α,5α respective arrangements, were transformed into corresponding methyl Z- and E-acrylates IVa-IXa. Peterson olefination by methyl trimethylsilylacetate gave mainly Z-isomers, whereas under conditions of Wittig-Horner reaction with trimethyl phosphonoacetate E-isomers were obtained in more stereoselective manner. THP-Ethers of methyl Z-acrylates IVa, VIa, and VIIIa were deprotected and from resulting 3-hydroxy derivatives IVb, VIb, and VIIIb the hemisuccinates IVd, VId, and VIIId and β-D-glucopyranosides IVf, VIf, and VIIIf were prepared.