4779-07-1Relevant academic research and scientific papers
Reactive E=C(p-p)?-Systeme, XVI. Trimethylstannylphosphanes of the Type Me3SnP(R)CF3 (R = Me, Et) as Phosphaalkene Precursors
Grobe, Joseph,Szameitat, Juergen
, p. 427 - 437 (2007/10/02)
Stannylphosphanes of the type Me3SnP(R)CF3 have been prepared by a multistep synthesis (Fig. 1) starting either with F3CPI2 or with P(NEt2)3.Due to the alkyl substituents, 1 and 2 show a higher thermal stability than the analogous perfluoroalkyl compounds Me3SnP(RF)2 (RF = CF3, C2F5).Pyrolysis of 1 and 2 at 380 deg C/1E-3 Torr gives the new phosphaalkenes RP=CF2 (R = Me, Et) as reactive intermediates collected at -196 deg C.They polymerize on the attempt to prepare diluted solutions even at very low temperatures.In case of the ethyl derivative the product (EtPCF2)x is a colourless polymer which on heating (500 - 600 deg C) yields a mixture of dimers (EtPCF2)2 (trans-, cis-1,3- and trans-1,2-diphosphetane: ratio 73:13.5:13.5). 1 and 2 have been used as equivalents of the phosphaalkenes RP=CF2 in one-pot reactions with 2,3-dimethylbutadiene and 1,3-cyclohexadiene, respectively.The labile P=C intermediates produced at 120 deg C are captured by the dienes affording the -cycloadducts 3-6 in good yields.Oxidation with sulfur gives the corresponding phosphane sulfides 7-10 in almost quantitative yields.New compounds were characterized by spectroscopic (NMR, MS, IR) and analytical methods. - Keywords: Preparation and Thermolysis of Me3SnP(R)CF3, Cycloaddition to Dienes, Phosphane Sulfides
