Abstract
We reported new oxa-Povarov reactions involving readily available diaryloxymethylacetals and benzothiophene-substituted alkenes; their [4+2]-cycloadditions were efficiently catalyzed by IPrAuSbF6 with high diastereoselectivity.And this new synthesis is to provide a rapid entry to a dihydrobenzopyran core that is commonly found in numerous biologically active natural compounds. Furthermore, we also used chiral catalyst (R)-(+)-BINAP(AuCl)2 with a cocatalyst NaBARF to catalyze this synthesis. We discovered copper-catalyzed aerobic oxidations of N-hydroxylamines to form nitrones. And with nucleophiles, we could get tetra-substituted nitrone by an one-pot reaction. On the other hand, we changed the structure of N-hydroxylamine substrate to undergo copper-catalyzed aerobic oxidations, with nucleophilic reagents like water and alcohols, we could successfully get β-oxoamides and 3-substituted 3-amino-2-en-1-ones two different products. Then we changed the reaction condition, we provided new products 2-allyl-3-oxoamides with molecular complexity, which involving a Claisen rearrangement.