Action of tetrabutylammonium tribromide with para-substituted chalcones in protic and aprotic media

Abstract

Bromination of the double bond of para-substituted chalcones under mild conditions in aprotic solvents is accomplished with high yields using tetrabutylammonium tribromide (TBABr3). In methanol, the main reaction is (α-β) bromomethoxylation. Stereoselectivity, regioselectivity, and chemioselectivity of this bromomethoxylation reaction are described. Keywords: bromination, bromomethoxylation, tetrabutylammonium tribromide, (α-β) dibromodihydrochalcones, α-bromo, β-methoxydihydrochalcones.