Alkylation of ketones with 3-bromomethyl-1,2-benzisothiazoles

The synthesis of 3-bromomethyl-1,2-benzisothiazole and its 5- and 7-methoxy derivatives has been accomplished. In alkylation reactions, these bromides were found to behave much like benzylic bromides; and in this respect they have been used successfully to alkylate strongly basic enolates, thus introducing a latent β-phenylethyl moiety in situations where β-phenylethyl bromide and phenacyl bromide give at best poor yields of alkylated product. In several cases, degradative procedures have been devised to remove the heteroatoms from the benzisothiazoyl system to provide the actual β-phenylethyl fragment; however, no generally applicable degradative method has yet been developed.