B(C6F5)3 catalysed reduction of para-quinone methides and fuchsones to access unsymmetrical diaryl- and triarylmethanes: elaboration to beclobrate

Abstract

A mild and efficient method for the synthesis of unsymmetrical diaryl- and triarylmethanes through a B(C₆F₅)₃ catalyzed reduction of para-quinone methides and fuchsones respectively, using the Hantzsch ester as a reducing source has been developed. Detailed mechanistic investigations revealed that the reaction actually proceeds through a Lewis acid–base pair complex derived from B(C₆F₅)₃ and the Hantzsch ester.