Reactions of N-cinnamoylaziridines by generation of aziridino ketyls from homolytic cleavage of Michael adducts

Abstract

High yields of the pyrrolidinones 2a, b are obtained from N-cinnamoylaziridines 1a, b and the carbanion ‘anthracene hydride’(anion of dihydroanthracene). Aziridino ketyls 3a, b are intermediates that probably arise by way of base-initiated homolytic fragmentation of an intermediate adduct. From reactions with xanthenyl anion X^– it can be deduced that Michael addition is the first step, perhaps in the absence of steric hindrance (1a) accompanied by carbonyl addition. Reversibility of the addition with X^– allows the irreversible nucleophilic ring-opening of 1a by X^– to dominate in long term runs where the ultimate product is the spiro piperidinone 14. The trityl anion Tr^– and 1a form a Michael adduct 26 that slowly homolyses to 3a giving finally the para substituted triphenylmethanes 22 and 23 which probably result from an S_RN1 chain reaction.