Sterically demanding, bioxazoline-derived N-heterocyclic carbene ligands with restricted flexibility for catalysis

J Am Chem Soc. 2004 Nov 24;126(46):15195-201. doi: 10.1021/ja045349r.

Abstract

A unique family of N-heterocyclic carbenes derived from bioxazolines (IBiox) suitable for application in transition-metal catalysis is described. The ligands are electron rich, sterically demanding, and have restricted flexibility. Their usefulness has been demonstrated in the Suzuki-Miyaura cross-coupling of sterically hindered aryl chlorides and boronic acids. For the first time, tetraortho-substituted biaryls with methyl and larger ortho-substituents have been synthesized from aryl chlorides using the Suzuki-Miyaura method.