Efficient Bromination of Alkenes and Alkynes Using Potassium Bromide and Diacetoxy Iodobenzene

Bromination of olefins with HBr and DMSO

A simple and inexpensive methodology is reported for the conversion of alkenes to 1,2-dibromo alkanes via oxidative bromination using HBr paired with dimethyl sulfoxide, which serves as the oxidant as well as cosolvent. The substrate scope includes 21 olefins brominated in good to excellent yields. Three of six styrene derivatives yielded bromohydrins under the reaction conditions.

Method for transforming alkynes into (E)-dibromoalkenes

The highly stereoselective bromination of alkynes has been realized by using copper(II) bromide as both the reacting partner and the catalyst, offering a generally efficient synthesis of (E)-dibromoalkenes. The reaction conditions are exceptionally mild, and a wide range of functional groups are well tolerated.