Products from diborane reduction of αβ-unsaturated ketones: trans-and cis-1β-acetoxy-8aβ-methyl-Δ5-octalin

Abstract

The reaction of 1β-acetoxy-8aβ-methyl-Δ^4α(5)-6-octalone with an excess of diborane followed by treatment of the resulting organoboranes with acetic anhydride affords in poor yield a mixture of two isomeric octalins which are determined to be trans- and cis-1β-acetoxy-8aβ-methyl-Δ⁵-octalin on the basis of spectral data and conversion of one of them into the known trans-8a-methyl-1-decalone. The spectral properties of the cis-isomer are found to be identical with those reported previously for an olefin obtained from a comparable reaction, but assigned the trans-configuration.