Regiospecificity of the Hydroboration of Some Steroidal trans-Dienes
Abstract
Hydroboration of 17β-hydroxy-3-methyleneandrost-4-ene gives 3β-hydroxymethyl-5α-androstan-4α,17β-diol whilst, contrary to previous reports, hydroboration of a steroidal 3,5-diene and a 4,6-diene affords not only the 4α,6α-diol but also the 3β,6β- and 4β,6α-diols from the 3,5-diene and the 4β,6α- and 4β,7β-diols from the 4,6-diene.