Reductive C2-Alkylation of Pyridine and Quinoline N-Oxides Using Wittig Reagents

Abstract

The ability to alkylate pyridines and quinolines is important for their further development as pharmaceuticals and agrochemicals, and for other purposes. Herein we describe the unprecedented reductive alkylation of pyridine and quinoline N-oxides using Wittig reagents. A wide range of pyridine and quinoline N-oxides were converted into C2-alkylated pyridines and quinolines with excellent site selectivity and functional-group compatibility. Sequential C-H functionalization reactions of pyridine and quinoline N-oxides highlight the utility of the developed method. Detailed labeling experiments were performed to elucidate the mechanism of this process.

Keywords: Wittig reagents; alkylation; methylation; pyridine N-oxides; regioselectivity.