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Updated: Oct 22, 2025

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Metathesis of P=C Bonds Catalyzed by N-Heterocyclic Carbenes
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
Abstract:
The catalytic metathesis of C=C bonds is a textbook reaction that has no parallel in the widely studied area of multiple bonds involving heavier p-block elements. A high-yielding P=C bond metathesis of phosphaalkenes (ArP=CPh2 , Ar=Mes, o-Tol, Ph) has been discovered that is catalyzed by N-heterocyclic carbenes (NHC=Me2 IMe, Me2 Ii Pr). The products are cyclic oligomers formally derived from ArP=PAr [i. e. cyclo-(ArP)n ; n=3, 4, 5, 6] and Ph2 C=CPh2 . Preliminary mechanistic studies of this remarkable transformation have established NHC=PAr (Ar=Mes, o-Tol, Ph) as key phosphinidene transfer agents. In addition, novel cyclic intermediates, such as, cyclo-(ArP)2 CPh2 and cyclo-(ArP)4 CPh2 have also been observed. This work represents a rare application of non-metal-based catalysts for transformations involving main-group elements.
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