REMARKABLE SELECTIVITY IN THE REACTION OF 1-TRITYL-2-LITHIOIMIDAZOLES WITH T-BUTYL HALOGENOACETATES

2-Lithio-1-triphenylinethylimidazoles react with t-butyl halogenoacetates to give a variety of products, the nature of which is cleanly determined by the halogen atom. With chloroacetate the products are chloromethyl ketones, while bromacetate gives di-t-butyl imidazolesuccinates, and iodoacetate yields iodoimidazoles. In each case 50% of the parent triphenylmethylimidazole is recovered from the reaction. When the triphenylmethyl substituent is replaced by the N,N-dimethylsulfamoyl group, reaction with bromoacetate is suppressed, but t-butyl chloroacetate and iodoacetate again give chloroketones and aryl iodides respectively.