An efficient method for the synthesis of vinylbromohydrin and vinylbromoalkoxy derivatives and cyclocarbonylation of alpha-allenic alcohols catalyzed by palladium chloride.

Vinylidenecyclopropanes undergo hydrobromination or alkoxybromination in the presence of N-bromosuccinimide and water or alcohols to give the corresponding vinylbromohydrin and vinylbromoalkoxy derivatives in moderate to excellent yields at room temperature. These vinylbromohydrin derivatives can be easily transformed to alpha-allenic alcohols in the presence of Et3N under mild conditions. In addition, the cyclocarbonylation of alpha-allenic alcohols with CO catalyzed by palladium chloride to give the corresponding lactones under different reaction conditions has been described.