α-Alkylation of ketones with primary alcohols catalyzed by a Cp*Ir complex bearing a functional bipyridonate ligand.

Abstract

A Cp*Ir complex bearing a functional bipyridonate ligand was found to be a highly effective and versatile catalyst for the α-alkylation of ketones with primary alcohols under extremely environmentally benign and mild conditions (0.1 equiv of Cs2CO3 per substrate, reflux in tert-amyl alcohol under an air atmosphere for 6 h). Furthermore, this complex also exhibited a high level of catalytic activity for the α-methylation of ketones with methanol. The mechanistic investigation revealed that the carbonyl group on the ligand is of critical importance for catalytic hydrogen transfer. Notably, the results of this study revealed the unique potential of Cp*Ir complexes bearing a functional bipyridonate ligand for the development of C-C bond-forming reactions with the activation of primary alcohols as electrophiles.