5518-61-6Relevant articles and documents
Linear Oligophosphaalkanes, XX. Alkali Metal and Trimethylsilyl Derivatives of PH-Functional Methylenebisphosphanes
Gol, Franjo,Hasselkuss, Gerd,Knueppel, Peter C.,Stelzer, Othmar
, p. 31 - 44 (2007/10/02)
The synthesis of the trimethylsilyl derivatives of the PH-functional methylenebisphosphanes, R2-n(Me3Si)nP-CH2-PR(SiMe3) (R = Me, iPr, tBu, Ph, 2,4,6-Me3C6H2; n = 0, 1) is reported.In the Li-phosphides R2-nLinP-CH2-PLiR used as reactive intermediates, a monomer-oligomer association equilibrium causes a rapid Li-exchange as indicated by the solvent and temperature dependent 31P and 7Li NMR spectrum of (iPr)2P-CH2-P(iPr)Li in various solvents (Et2O, THF and MTHF) in the temperature range from 30 to -110 deg C.For the syntheses of the Me- and Ph-substituted PH-functional methylenebisphosphanes R2P-CH2-PRH and RHP-CH2-PRH (R = Me, Ph) the chlorophosphane Cl2P-CH2-PCl2 is used as a starting material.Bifunctional substituents ( and ) are employed for the first time as protecting groups to block one or two PCl-functions in Cl2P-CH2-PCl2.Cleavage of the PN-bonds in the five membered ring systems (R = Me, Ph) with HCl affords the P-substituted methylenebis-chlorophosphanes RClP-CH2-PClR in satisfactory yields.The compounds have been characterized by 1H, 13C and 31P NMR spectroscopy.Within homologous substitution series of methylenebisphosphanes, e.g.R2P-CH2-PR2-nHn the coupling constants 2J(PP) seem to reflect conformational changes at the PCP-skeleton. - Keywords: Functional Methylenebisphosphanes, Bifunctional Protecting Groups, Lithium and Trimethylsilyl Derivatives, Dynamic Li-Exchange, NMR Spectra
