Reduction of Steroid and Triterpenoid α,β-Unsaturated Ketones with Lithium/Ethylenediamine
Reduction of less sterically hindered ketone, glochidone (1) with lithium/ethylenediamine (Li/EDA) leads to the reduction of the double bond followed by that of the carbonyl group to afford thermodynamically stable alcohol, lupanol (1b).The sterically hindered α,β-unsaturated ketones such as 11-keto-triterpenoids also furnish saturated alcohols but in small proportions; the other compounds formed are obtained with reduction of the carbonyl group accompanied by dehydration or even deoxygenation.