Pd(OAc)-Catalyzed Synthesis of Imidazo[1,2-]phenanthridines via a Sequential Ullmann Coupling and Oxidative Coupling Dehydrogenation.

The Ullmann coupling and oxidative coupling dehydrogenation reactions have occurred sequentially, catalyzed by Pd(OAc), which unexpectedly yielded fused imidazo[1,2-]phenanthridine derivatives in good to high yields. Structural analysis of the intermediate and final products indicated that the protocol did not include C-H and N-H arylation.

Silver-Catalyzed Radical Umpolung Cross-Coupling of Silyl Enol Ethers with Activated Methylene Compounds: Access to Diverse Tricarbonyl Derivatives.

A silver-catalyzed protocol for the intermolecular radical umpolung cross-coupling protocol of silyl enol ethers with activated methylene compounds is disclosed. The protocol exhibits excellent functional group tolerance, enabling the expedient preparation of a variety of tricarbonyl compounds. Preliminary mechanistic investigations suggest that the reaction proceeds through a process involving free radicals in which silver oxide has a dual role, acting as both a catalyst and a base.