Bis(amino)cyclopropenium Salt Catalyzed 1,6-Conjugate Addition of 2-Naphthols to p-Quinone Methides

Abstract

Bis(amino)cyclopropenium salt has been utilized as a hydrogen-bond donor catalyst for the 1,6- conjugate addition of 2-naphthols to para-quinone methides. Here the bis(amino)cyclopropenium salt acts as a Brønsted acid. This transformation occurs at mild conditions and is tolerant to a variety of functional groups. This protocol provides an easy and straightforward access to various unsymmetrical triarylmethanes in good to excellent yields.