Studies on conformationally controlled reactions of α,β-unsaturated macrolides

Abstract

Allylic oxidation of 13- to 15-membered simple α,β-unsaturated (ω − 1)-macrolides was observed to be highly diastereoselective. Also reduction and Grignard addition reactions of α,β-unsaturated γ-ketomacrolides proceeded with high diastereoselectivity. The selectivity is controlled by the preferred conformations of the macrocyclic rings. The Boltzmann distribution of the starting material conformations can be used to predict the diastereoselectivity of these reactions.