Preparation and Utility of Dianions from N-tert-Butylthiophene-2-sulfonamide

Article abstract of DOI:10.1021/jo00013a034

Metalation of N-tert-butylthiophene-2-sulfonamide with n-butyllithium occurs competitively at the 3- and 5-position of the thiophene ring.Equilibration of the initial mixture of carbanions or metalation with lithiumdiisopropylamide allows selective formation of the N,5-dilithiothiophenesulfonamide 7.This dianion is useful for the preparation of a number of 5-substituted thiophene-2-sulfonamides.