Copper-Salt-Promoted Carbocyclization Reactions of α-Bromo- N -arylacylamides

A mild and convenient synthetic method for oxindoles and α-arylacylamides bearing an all carbon quaternary stereocenter from the readily available α-bromo-N-arylacylamides has been developed. This Cu(acac)₂/Phen-promoted radical cyclization reaction, via the intramolecular radical cyclization onto the aryl moiety, can proceed in two different routes depending on the substituents on the nitrogen atom. In this transformation, oxindoles and α-arylacylamides were formed in high chemoselectivity. A variety of useful functional groups such as methoxy, fluoro, chloro, bromo, methoxycarbonyl, and cyano are compatible with the reaction conditions. The use of inexpensive, readily available Cu(acac)₂ and Phen makes this protocol very efficient and practical.