title: C-C bond insertion of a complexed phosphinidene into 1,6-methano[10]annulene.
abstract: Reaction of electrophilic phosphinidene complex [MePW(CO)5] with 1,6-methano-[10]annulene results in the sole formation of the isomeric C-C insertion products 6 c (main) and 6 d (minor). The single-crystal X-ray structure of the complexed 1,7-methano-3-phospha[11]annulene (6 c) shows a syn-W(CO)5 group at the exo bent phosphorus. The structure displays C-C bond alternation without bonding between the bridgehead carbon atoms. Density functional theory calculations indicate 6 c to result from a concerted disrotatory ring opening of an undetected tricyclic exo-syn phosphirane intermediate. The endo-anti phosphirane cannot undergo ring expansion, due to the high barrier that is associated with an intramolecular antara-antara retro Diels-Alder reaction. The stabilizing effect of transition-metal coordination is discussed.
authors.affiliation: Vrije Universiteit, FEW, Department of Chemistry, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
authors.forename: Rosa E
authors.initials: RE
authors.lastname: Bulo
authors.forename: Linda
authors.initials: L
authors.lastname: Trion
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Ehlers
authors.forename: Fransiscus J J
authors.initials: FJ
authors.lastname: de Kanter
authors.forename: Marius
authors.initials: M
authors.lastname: Schakel
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Spek
authors.forename: Koop
authors.initials: K
authors.lastname: Lammertsma