Synthesis of 2-[1-(Alkoxycarbonyl)alkyl]-3-methylbenzothiazolines and 3-Methyl-2-(2-oxoalkyl)benzothiazolines by the Direct Alkylation of Lithium Enolates with 3-Methylbenzothiazolium Salts

A variety of lithium enolates derived from esters and ketones could be readily alkylated with 3-methylbenzothiazolium salts to give the novel α-(benzothiazolinyl) esters and ketones, 2-[1-(alkoxycarbonyl)alkyl]3-methylbenzothiazolines and 3-methyl-2-(2-oxoalkyl)benzothiazolines in good yields, respectively.