Benzeneselenenyl p-toluenesulfonate (1) was generated in situ by the reaction of silver p- toluenesulfonate with benzeneselenenyl chloride in acetonitrile. The reagent reacted with acetylenes by electrophilic 1, a-addition to afford the & (phenylseleno) vinyl p- toluenesulfonates 2-12, generally in high yield. The latter were formed preferentially by anti addition, but with poor regioselectivity, unless a strongly orienting group (eg, phenyl) was ...
