Direct bromoalkoxylation of enones under acid-free conditions

Abstract

Difunctionalization of alkene conceptually serves as an appealing way to generate molecular complexity and synthesis of functional molecules. Bromoalkoxylation is an important method for 1,2-difunctionalization of alkene. However, this transformation generally requires an oxidant or a strong activator like Brønsted acid. Herein, we report a direct protocol for bromoalkoxylation of enone-type alkenes under acid-free conditions. Moreover, this transformation demonstrates various advantages including simple operation, mild reaction condition, high yield, exclusive diastereoselectivity, and broad substrate scope and functional group tolerance. This protocol could also be extended to α,β-unsaturated ester and amide substrates and ethoxyl nucleophile, thus providing a practical way for vicinal difunctionalization of activated olefin compounds.