Copper-catalyzed oxidative dehydrogenative [3 + 2] annulation of oximes with α-amino ketones: entry to 3-aminopyrroles

Abstract

An unprecedented copper-catalyzed oxidative dehydrogenative [3 + 2] annulation of O-acyl oximes containing α-C(sp³)–H bonds with α-amino ketones for the preparation of 3-aminopyrroles is developed. This method uses O-acyl oximes as both internal oxidants and three-atom-unit components combined with the copper catalyst to drive catalytically generated oxime nitrogen-centered radicals and oxidative dehydrogenation of the α-amino ketones to form the key 2-iminoethan-1-one intermediates, enabling site-selective cleavage of the multiple α-C(sp³)–H bonds in O-acyl oximes and α-amino ketones to create two new bonds, including a C(sp²)–C(sp²) bond and a C(sp²)–N bond, between the carbon atoms and the nitrogen atom in a cross-selective fashion.