A convenient synthesis of the side-chain of sterols
作者:T. Schmittberger、D. Uguen
DOI:10.1016/0040-4039(95)02075-6
日期:1996.1
Potassium t-butoxide-induced Ramberg-Bäcklund rearrangement of chlorosulfones formed from a cyclopregnane-20-thiomethanol derivative has been shown to give Δ22-unsaturated steroids with high trans stereoselectivity.
Enzyme-catalysed differentiation of hydroxy groups in a C2v-shaped tetraol-sulfide, combined with a E-stereoconvergent Ramberg-Bäcklund process, allowed to prepare pure (2S)-2,3-dimethyl-1-iodobutane, which could be coupled with a 3,5-cyclopregnane-20-thiomethanol derivative so as to give an efficient precursor of the title vegetal hormone.