Pentafluorobenzoic Acid Catalyzed 1,6-Conjugate Addition of Indoles to p-Quinone Methides

Abstract

Pentafluorobenzoic acid has been utilized as a non-covalent Br Ø nsted acid catalyst for the 1,6- conjugate addition of indoles to para-quinone methides. This transformation tolerant to a variety of functional groups and occurs in mild conditions. This methodology provides an easy and straightforward access to a set of unsymmetrical diarylindolylmethanes in moderate to good yields.