RADICAL-CATION INITIATED CYCLOADDITION REACTIONS BETWEEN 2-VINYLINDOLES AND BETA-SUBSTITUTED ENAMINONITRILES

Electron transfer initiated cycloaddition reactions between 2-vinylind oles, acting as heterodienes, and beta-substituted enaminonitriles lea d to different cycloaddition products depending on the substituents. I nitiated by potentiostatically controlled electrolysis, an anellation of a cyclopropanated five-membered ring system to the diene yielding c yclopropapyrrolo[1,2-a]indoles can be achieved in just one reaction st ep. Interestingly, the formation of a cyclopropane ring system takes p lace in reaction mechanisms which involve radicals and radical cations . In addition to these products, [4+2]-cycloaddition products with sub sequent [1,4] dialkylamino shifts can also be formed. The formation of both products can be attributed to new reaction pathways via radical cation intermediates.