Facile Synthesis of -Tribromomethyl andDibromomethylenated Nitroalkanes viaConjugate Addition of Bromoform toNitroalkenes

摘要

Addition of bromoform to conjugated nitroalkenes in thepresence of Mg provided β-tribromomethyl nitroalkanes ingood to excellent yields and diastereoselectivity. These novelMichael adducts, formed under radical conditions, underwentelimination of HBr in the same pot under reflux to affordβ-dibromomethylenated nitroalkanes in good yield. Alter-natively, a one-pot high yielding synthesis of the dibromideswas possible under anionic conditions via LDA mediatedaddition of bromoform to nitroalkenes.