Zn(OTf)2-catalyzed 1,6-conjugate addition of N-heterocycles to p-Quinone methides: easy access to N-diarylmethyl-substituted heterocycles

Abstract

A highly regioselective N-alkylation of various aromatic aza-heterocycle bearing N-H moiety like pyrazole, indazole, benzotriazole and saccharine with paraquinone methides as ideal 1,6-acceptor promoted by Zn(OTf)2 catalyst was developed. This base free protocol works in mild conditions and has a wide range of substrate scope with moderate to excellent yields.