title: General one-pot, three-step methodology leading to an extended class of N-heterocyclic cations: spontaneous nucleophilic addition, cyclization, and hydride loss.
abstract: A new class of phenanthridinium derivative has been isolated from the reaction of 2-bromoethyl-phenanthridinium bromide with a range of primary amines in excellent yields. The reaction pathway is unprecedented and proceeds via three cascade steps: nucleophilic attack of a primary amine on the iminium moiety of a heteroaromatic ring system and cyclization to form a five-membered ring, followed by hydride loss to yield a rearomatized dihydro-1H-imidazo[1,2-f]phenanthridinium derivative. A range of NMR phase transfer experiments were carried out to elucidate the mechanistic pathway, and the methodology has been further developed by means of a biphasic system using N-bromosuccinimide as a co-oxidizing agent. The method has also been extended to other N-heterocyclic cation derivatives such as quinolinium and quinazolinium.
authors.affiliation: Department of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
authors.forename: Alexis D C
authors.initials: AD
authors.lastname: Parenty
authors.forename: Louise V
authors.initials: LV
authors.lastname: Smith
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Pickering
authors.forename: De-Liang
authors.initials: DL
authors.lastname: Long
authors.forename: Leroy
authors.initials: L
authors.lastname: Cronin