title: Generation and cyclization of unsaturated carbamoyl radicals derived from S-4-pentynyl carbamothioates under tin-free conditions.
abstract: The radical reaction of benzenethiol with S-4-pentynyl carbamothioates provides a valuable protocol for the tin-free generation of carbamoyl radicals, which arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals. This procedure can be usefully employed to achieve N-benzylcarbamoyl radical 5-exo and 4-exo cyclizations leading, respectively, to pyrrolidinones and azetidinones, although, for the latter, it seems of lesser utility. Novel evidence is presented that N-tosyl-substituted carbamoyl radicals display a peculiar tendency to yield the corresponding isocyanate by beta-elimination of the tosyl radical.
authors.affiliation: Dipartimento di Chimica Organica A. Mangini, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Benati
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bencivenni
authors.forename: Rino
authors.initials: R
authors.lastname: Leardini
authors.forename: Matteo
authors.initials: M
authors.lastname: Minozzi
authors.forename: Daniele
authors.initials: D
authors.lastname: Nanni
authors.forename: Rosanna
authors.initials: R
authors.lastname: Scialpi
authors.forename: Piero
authors.initials: P
authors.lastname: Spagnolo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanardi