1,6-conjugate Addition Of 2-alkyl-azaarenes To Para-quinone Methides

Recently,para-quinone methides(p-QMs)have been widely utilized in 1,6-conjugate addition as a classical Michael acceptor.Meanwhile,2-alkylazaarenes were used as electrophiles via Lewis acids or Br?nsted acids catalysis.Combining p-QMs and 2-alkyl-azaarenes was hoped to develop a new method to synthesis triarylethane compounds.Herein,we reported the Hf(OTf)4 catalyzed 1,6-conjugate addition of 2alkyl-azaarenes to p-QMs.Under the optimized condition,33 triarylethane compounds have been synthesized in good to excellent yield.The catalyst loading could be reduced to 1 mol%.Studies to scale-up reaction and product derivatization were also presented.