Metalation and Oxidative Coupling of the Unique Cyclic Silylphosphanes ( i Pr 2 Si) 3 PH and ( i Pr 2 Si) 4 PH

The cyclic tetrasilaphosphane ( i Pr 2 Si) 4 PH ( 6 ) can be synthesised in five steps starting from diisopropylchlorsilane and [Li(DME)PH 2 ]. Subsequent lithiation and oxidative coupling with dibromethane yields the diphosphane [( i Pr 2 Si) 4 P] 2 ( 7 ). In an analogous manner the bicyclic diphosphane [( i Pr 2 Si) 3 P] 2 ( 3 ) can be obtained from the cyclic trisilaphosphane ( i Pr 2 Si) 3 PH ( 1 ). Moreover, the reaction of 1 with [W(CO) 5 THF] yields the Lewis acid–base complex [( i Pr 2 Si) 3 P(H)W(CO) 5 ] ( 2 ), and the trimeric lithiumphoshpanide [( i Pr 2 Si) 4 PLi] 3 ( 8 ) occurs from the reaction of 6 with n BuLi in heptane. All intermediate and final products are characterised by multinuclear NMR spectroscopy, IR spectroscopy and mass spectrometry. Furthermore, the crystal structures determined by X‐ray diffraction are described for compounds 2 , 3 , 6 , 7 and 8 .(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)