Copper-catalyzed aerobic oxidations of 3-N-hydoxyaminoprop-1-ynes to form 3-substituted 3-amino-2-en-1-ones: oxidative Mannich reactions with a skeletal rearrangement.

Cu-catalyzed aerobic oxidations of readily available 3-N-hydroxyaminopro-1-ynes with water, alcohols, or thiols to form diverse 3-substituted 3-amino-2-en-1-ones are described. The utility of this catalysis is manifested by a wide scope of applicable N-hydroxyl propargylamines and nucleophiles, thus enabling the design of one-pot cascade or two-step sequential reactions. Besides synthetic significances, such oxidative Mannich reactions are mechanistically interesting because structurally reorganized products were obtained.

Gold-catalyzed oxa-Povarov reactions for the synthesis of highly substituted dihydrobenzopyrans from diaryloxymethylarenes and olefins.

Oxa-Povarov reactions involving readily available diaryloxymethylarenes and aryl-substituted alkenes are reported. Their [4+2] cycloadditions were efficiently catalyzed by IPrAuSbF6 (IPr=1,3-bis(diisopropylphenyl)imidazol-2-ylidene) with high diastereoselectivity. Product analysis revealed that the reactions likely proceed by a stepwise ionic mechanism, because both E- and Z-configured β-methylstyrene gave the same cycloadducts in the same proportions.