Electron Transfer‐Catalyzed Diels–Alder Reactions with 2‐Vinylindoles

A Diets–Alder reaction between two electronrich components is possible with electron transfer catalysis. 2-Vinylindole radical cations generated in this way react with 1,3-cyclohexadienes to yield highly substituted carbazole derivatives such as 1. This reaction is interesting above all for the synthesis of indole alkaloids. R1 - R3 are, for example, H, Me, iPr, Ph.