Ligand-Controlled Regioinduction in a PHOX-Ni Aryne Complex

Abstract

Phosphinooxazoline (PHOX) ligands have been used to control the regio- and enantioselectivity in a wide variety of metal-catalyzed reactions. Despite their widespread use, PHOX ligands have never been studied in metal-aryne complexes. Herein we report the first example of a PHOX-Ni aryne complex. As demonstrated in other systems, the differentiated P versus N donors and different steric environments of the unsymmetric ligand are able to induce regiocontrol. A 81:19 mixture of o-methoxy substituted aryne complexes is observed. Single-crystal X-ray crystallographic analysis, UV/vis spectroscopy, and cyclic voltammetry are used to gain further insight into the molecular and electronic structure of these complexes. Lastly, a methylation/deuteration sequence shows retention of the PHOX ligand-induced regiocontrol in the difunctionalized products and that the regiospecificity of these difunctionalizations is due to the trans influence of the P donor.