The ‘Hirao reduction’ revisited: a procedure for the synthesis of terminal vinyl bromides by the reduction of 1,1-dibromoalkenes

A convenient procedure for the synthesis of vinyl bromides is described, which involves the selective reduction of the corresponding 1,1-dibromoalkenes with dimethylphosphite and triethylamine. The 1,1-dibromoalkenes are obtained in excellent yields from the corresponding aldehydes via olefination with carbon tetrabromide and triphenylphosphine.