Promotion of phosphaalkyne cyclooligomerisation by a Sb(v) to Sb(iii) redox process.
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.
Fish
Cheryl
C
School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 1TS.
Green
Michael
M
Kilby
Richard J
RJ
McGrady
John E
JE
Pantazis
Dimitrios A
DA
Russell
Christopher A
CA