Expedient access to unsymmetrical triarylmethanes through N-heterocyclic carbene catalysed 1,6-conjugate addition of 2-naphthols to para-quinone methides

Abstract

The utility of N-heterocyclic carbene as a Brønsted base catalyst for the synthesis of functionalised unsymmetrical triarylmethanes from 2-naphthol and para-quinone methides is described. This protocol allows the installation of naphthyl substituents on p-quinone methides through 1,6-conjugate addition to deliver the unsymmetrical triarylmethanes in good to excellent yields. Mild reaction conditions and 100% atom economy make this method synthetically advantageous over the other hitherto known methods.