[4 + 2]-Cycloaddition Reactions between beta-Acceptor-Substituted Enamines and 2-Vinylindole Radical Cations Acting as Hetero-Dienes.
[4 + 2]-Cycloaddition reactions between 2-vinylindoles acting as hetero-dienes and beta-acceptor substituted cyclic and acyclic enamines can be induced by formation of 2-vinylindole radical cations either via anodic oxidation or photoelectron transfer (PET) using catalytic amounts of triarylpyrylium tetrafluoroborates as sensitizers. In this way, pyrido[1,2-a]indoles or indolo[1,2-a]hexahydro-1,8-naphthyridines are formed in one step with complete regio- and stereochemical control.
Gürtler
Christoph F.
CF
Institut für Organische Chemie der Technischen Universität Berlin, Strasse des 17 Juni 124, D-10623 Berlin, Germany, and Institut für Organische Chemie der Universität Bonn, Gerhard-Domagk Str. 1, D-52121 Bonn, Germany.
Steckhan
Eberhard
E
Blechert
Siegfried
S