Polymer-supported strong Lewis acid phosphonium cation catalysis applied to sydnone synthesis

Abstract

Organochlorophosphonium P(V) species are strong Lewis acids deriving from a low-lying σ* orbital at P opposite to Cl. Herein, applying this strong acidity to heterogenous reactivity, we introduce polymer-supported phosphorus(V)-mediated Lewis acid catalysis. Key to this innovation is the use of a recyclable solid support Merrifield resin P(V) Lewis acid catalyst with demonstrated utility for the one-pot synthesis of sydnones. This concept of pnictogen P(V) Lewis acid catalysis is simple to apply, selective, and benefits from mild conditions with short reaction times. Further, experimental and computational findings reveal the crucial mechanistic role of phosphonium cation P(V) species in these reactions.