Regio‐ and Stereoselective Synthesis of Vicinal ( Z )‐Dihaloalkenylsilanes from Silyl Ethynylarenes

The direct access to ( Z )‐(1‐bromo‐2‐chloro‐2‐arylvinyl)triisopropylsilane through formal addition of BrCl to triisopropylsilyl ethynylarene was explored. BrCl was generated in situ from commercially available TMSCl and N ‐bromosuccinimide. This simple protocol enabled highly efficient regio‐ and stereoselective bromochlorination, bis‐bromination, and bis‐chlorination of the triple bond on a gram scale in the syn mode. It thus provided a potentially diverse scaffold for adaptable preparation of differently all‐carbon tetrasubstituted olefins.