%0 Journal Article %A Borst, Mark L. G. %A Bulo, Rosa E. %A Gibney, Danièle J. %A Alem, Yonathan %A J. J. de Kanter, Frans %A Ehlers, Andreas W. %A Schakel, Marius %A Lutz, Martin %A Spek, Anthony L. %A Lammertsma, Koop %D 2005 %T 3H-Benzophosphepine Complexes:  Versatile Phosphinidene Precursors %U https://acs.figshare.com/articles/journal_contribution/3_i_H_i_Benzophosphepine_Complexes_Versatile_Phosphinidene_Precursors/3253207 %R 10.1021/ja054885w.s002 %2 https://acs.figshare.com/ndownloader/files/5088568 %K benzophosphepine complexes %K phosphinidene %K hydrophosphination step proceeds %K ML %K diethynylbenzene %X The synthesis of a variety of benzophosphepine complexes [R = Ph, t-Bu, Me; MLn = W(CO)5, Mo(CO)5, Cr(CO)5, Mn(CO)2Cp] 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. %I ACS Publications