Synthesis of 3-phenylsulfonyl-2-trifluoromethyl-1H-indoles: A copper catalyzed cyclization approach

Abstract

3-Sulfonyl and 3-aroylindoles have attracted special attention because of their interesting biological activities, particularly for the development of antiviral and anticancer compounds. Based on the importance of the trifluoromethyl group in biological active molecules, we have developed a synthetic pathway for the preparation of a series of 3-phenylsulfonyl-2-trifluoromethyl-1H-indoles in two steps starting from readily available methyl-phenylsulfones. The starting methylsulfones underwent reaction with trifluoroacetimidoyl chlorides using LDA/THF at −40°C to produce a mixture of trifluorometylimino/enamino-β-sulfonylphenyl intermediates, which were then cyclized using a copper (II) catalyst to give the title compounds in moderate to good yield.