Electrophilic additions to allenes can occur with attachment of the electrophile to either the central or terminal carbons of the allene linkage. Such reagents as sulfenyl halides, la molecular halogens, lb and mercury saltslc seem to add regiospecifically and stereospecifically to the central atom, while hydrogen halide additionld and acid-catalyzed hydrationle generally occur with terminal orientation. lf We recently found2 that allenic ...
