3<i>H</i>-Benzophosphepine Complexes: Versatile Phosphinidene
Precursors
Mark L. G. Borst
Rosa E. Bulo
Danièle J. Gibney
Yonathan Alem
Frans J. J. de Kanter
Andreas W. Ehlers
Marius Schakel
Martin Lutz
Anthony L. Spek
Koop Lammertsma
10.1021/ja054885w.s002
https://acs.figshare.com/articles/journal_contribution/3_i_H_i_Benzophosphepine_Complexes_Versatile_Phosphinidene_Precursors/3253207
The synthesis of a variety of benzophosphepine complexes [R = Ph, <i>t-</i>Bu, Me; ML<i><sub>n </sub></i>= W(CO)<sub>5</sub>,
Mo(CO)<sub>5</sub>, Cr(CO)<sub>5</sub>, Mn(CO)<sub>2</sub>Cp] by two successive hydrophosphinations of 1,2-diethynylbenzene is
discussed in detail. The first hydrophosphination step proceeds at ambient temperature without additional
promoters, and subsequent addition of base allows full conversion to benzophosphepines. Novel benzeno-1,4-diphosphinanes were isolated as side products. The benzophosphepine complexes themselves serve
as convenient phosphinidene precursors at elevated, substituent-dependent temperatures (>55 °C). Kinetic
and computational analyses support the proposal that the phosphepine−phosphanorcaradiene isomerization
is the rate-determining step. In the absence of substrate, addition of the transient phosphinidene to another
benzophosphepine molecule is observed, and addition to 1,2-diethynylbenzene furnishes a delicate bidentate
diphosphirene complex.
2005-12-07 00:00:00
benzophosphepine complexes
phosphinidene
hydrophosphination step proceeds
ML
diethynylbenzene