Stereoselective Synthesis of Polycycles Containing an Aziridine Group: Intramolecular aza-Diels-Alder Reactions of Unactivated 2H-Azirines with Unactivated Dienes.

Vinyl azide with a pendent diene can undergo thermal decomposition to a related azirine intermediate, which was used immediately in an intramolecular aza-Diels-Alder reaction to furnish an aziridine-containing trans-fused tricyclic core structure with excellent stereoselectivity. The method provides a facile entry to complex polycyclic alkaliods which can be further elaborated by ring-opening reactions and ring expansion of the aziridine moiety, as well as by dihydroxylation of the alkene group.

An efficient approach to 1,2,3-trisubstituted indole via rhodium catalyzed carbene C(sp(3))-H bond insertion.

A method for convenient synthesis of N-alkyl-2-aryl-indole-3-carbaldehyde has been described. A variety of highly valuable indolyl aldehydes have been prepared through this method. Electron donating groups on both aromatic rings (anilinyl and benzyl) facilitate the formation of the desired products. A benzylic C-H insertion by rhodium carbene is the key step for this transformation.