Oxybromination of Ethynylbenzene Catalysed by Molybdenum Complexes in Organic Solvent and in Ionic Liquids

Abstract

Abstract The molybdenum(VI)‐catalysed oxybromination of ethynylbenzene was performed with hydrogen peroxide as oxidant and potassium bromide as source of bromine, in a two‐phase water/solvent system, where solvent was either dichloromethane or an ionic liquid. The selectivity was toward 1,2‐dibromostyrene when performed in water/dichloromethane. In ionic liquids better yields and shorter reaction times were obtained that, together with the complete ethynylbenzene conversion and the preferred formation of α,α‐dibromoacetophenone, make the reaction synthetically useful.