ON THE PREPARATION OF N-ACYLPYRROLES AND THEIR USE IN THE SYNTHESIS OF KETONES

Two methods for the preparation of N-aeylpyrroles have been studied: ( a) the reaction between pyrrole and N-acylimidazoles and (b) the oxida tion of amides of 3-pyrroline. The reactions between N-acylpyrroles an d organolithium compounds can be directed to give ketones in good yiel ds. The initially formed tetrahedral intermediates in these reactions are relatively stable and pyrrolylcarbinols are isolable intermediates . A Reformatsky-Claisen type ring-closure gave a more than doubled yie ld when an N-acylpyrrole group was used as an electrophile instead of an ester group; the increased stability of the initially formed tetrah edral intermediate presumably accounts for the observed result.