New 11,13-Dienone Analog of Cloprostenol

Abstract

Cloprostenol methyl ester was converted to the corresponding Δ^11,13-15-keto analog through 9,11-dihydroxy-15-oxo derivative which was subjected to exhaustive acylation and DBU-promoted removal of the 11-acetoxy group. The key stages of the transformation included protection of the 9,11-dihydroxy functionality of cloprostenol methyl ester via conversion to cyclic phenylboronate, in situ oxidation of the unprotected 15-hydroxy group of the latter, and exhaustive acetylation to obtain the corresponding diacetate as precursor to the target compound. An alternative synthetic path starting from 9α,11α-O-bis[tert-butyl(di-phenyl)silyl]-15-oxo derivative of cloprostenol methyl ester has also been proposed.