An epoxide-opening cyclization/double Smiles rearrangement cascade approach to N-aryl-1,4-benzoxazines and N-arylindolines

Abstract

Reported herein is a transition-metal-free protocol for a regio- and diastereoselective synthesis of hydroxyalkyl group-embedded N-arylbenzo[b][1,4]oxazines and N-arylindolines based on an epoxide-opening cyclization/double Smiles rearrangement cascade of p-nosylamide-tethered epoxides. To the best of our knowledge, this is the first report of the integration of epoxide-opening cyclization with Smiles rearrangement in a cascade fashion, enabling simultaneous construction and N-arylation of N-heterocycles. The reaction employs substrates derived from commercially available 2-nitrophenols and easily accessible allylic halides/alcohols, and exhibits a broad substrate scope and delivers the products in high yields.