General Method for the Suzuki Miyaura Cross-Coupling of Amides Using Commercially Available, Air-and Moisture-Stable Palladium/ NHC (NHC = N-Heterocyclic Carbene) Complexes

The direct Suzuki Miyaura cross-coupling of amides catalyzed by Pd-NHC complexes is reported. Using a single protocol, commercially available, air-and moisture stable (NHC)Pd(R-allyl)Cl complexes can effect Suzuki Miyaura cross-coupling of a wide range of amides with arylboronic acids in very good yields. The studies described herein represent the use of versatile Pd-NHC complexes as catalysts for transition-metal-catalyzed cross-coupling of amides by N-C bond activation. The Pd-NHC catalysts provide a significant improvement over all current Pd-PR3 systems employed for the amide N -C bond activation. Mechanistic studies provide strong support for the development of a unified reactivity scale of the amide bond for the generation of aryl-metal intermediates.