Regioselective synthesis of ring a polymethylated steroids in the androstane series

H Künzer, G Sauer, R Wiechert

Index: Kuenzer, Hermann; Sauer, Gerhard; Wiechert, Rudolf Tetrahedron, 1989 , vol. 45, # 20 p. 6409 - 6426

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Citation Number: 7

Abstract

Properly protected derivatives 14 and 20 of the common precursor 17β-hydroxy-1-methyl-5α- androst-1-en-3-one (13) have been transformed in a regioselective manner into highly methylated androsta-1, 4-diene-3, 17-dione derivatives 6–8. Access to the manifold of 1, 4- dimethylated derivatives was gained by methylation of the kinetic lithium dienolate derived from 20, while thiomethylation of 14, via the thermodynamic dienolate or an equivalent, ...