Rhodium(III)-Catalyzed N-Nitroso-Directed C–H Olefination of Arenes. High-Yield, Versatile Coupling under Mild Conditions

Abstract

N-nitroso compounds are a versatile class of organic structures that allow expedient access to a diversity of synthetically useful architectures through demonstrated reactivities. We report herein the development of a Rh(III)-catalyzed N-nitroso-directed methodology for the ortho-olefination of arenes. The heightened reactivity endowed by the N-nitroso group translates to mild reaction conditions, high reaction yields, and synthetic compatibility of otherwise elusive substrates (e.g., an unactivated olefin, 1-octene). Comprehensive mechanistic studies on the electronic effect, deuterium exchange, kinetic isotope effect, kinetic profile, and numerous Rh(III) complexes have established [RhCp*](2+) as the catalyst resting state, electrophilic C-H activation as the turnover-limiting step, and a five-membered rhodacycle as a catalytically competent intermediate. The ability to elaborate the N-nitroso moiety to an amine functionality provides a seminal example of the innumerable synthetic possibilities offered by this transformable directing group.