title: Promotion of phosphaalkyne cyclooligomerisation by a Sb(v) to Sb(iii) redox process.
abstract: A high yield of the tetraphosphaladderene, anti-tetraphosphatricyclo[4.2.0.0(2,5)]octa-3,7-diene, is obtained from reaction of the zirconocene 1,3-diphosphabicyclo[1.1.0]butane with Ph(2)SbCl(3) in THF or CH(2)Cl(2). Exploration of the reaction pathway using density functional theory suggests that an envelope-type adduct of Ph(2)SbCl and 1,3-diphosphabicyclo[1.1.0]butane plays a pivotal role in the reaction. The zwitterionic character of this intermediate species allows it to act simultaneously as both an ene and an eneophile, and a symmetry-allowed bimolecular reaction leads to the tetraphosphaladderene species via a spirocyclic intermediate.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 1TS.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Fish
authors.forename: Michael
authors.initials: M
authors.lastname: Green
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kilby
authors.forename: John E
authors.initials: JE
authors.lastname: McGrady
authors.forename: Dimitrios A
authors.initials: DA
authors.lastname: Pantazis
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Russell