80431-44-3Relevant articles and documents
Ungesaettigte Silicium- und Germaniumverbindungen XVI. Stabilisierung des Labilen Silaethens Me2Si=C(SiMe3)2 durch Adduktbildung mit Donoren. Reaktivitaet von Me2Si=C(Si(Me3)2NMe3
Wiberg, Nils,Koepf, Hubert
, p. 9 - 18 (1986)
Silaethene Me2Si=C(SiMe3)3 (1), unstable at -100 degC with regard to dimerization, forms an adduct Me2Si=C(SiMe3)2NMe3 (3) with trimethyl amine, metastable at 0 degC.It decomposes thermally to give 1 and NMe3 and can, therefore, serve as a source of 1.With 1 as an intermediate, the adduct 3 reacts with butadiene, cyclopentadiene, 2,3-dimethylbutadiene, Ph2C=NSiMe3, t-BuN3, isobutene, or acetone giving either cycloadducts or ene reaction products.Adduct 3 reacts with ROH (R0H, Me, t-Bu, Ph) to yield insertion products, probably by way of a proton adduct of 3, but not via 1.Other donors (D) of which NMe3 is an example form adducts 1D, producing a new class of silicon compounds.As the Lewis basicity of D, relative to 1, decrease (F- >NMe3>NEt3>Br->THF), the resistance to decomposition of the adducts 1D to the dimer of 1 and D also decreases.
Storing of the Labile Silaethene Me2Si=C(SiMe3)2 with Benzophenone
Wiberg, Nils,Preiner, Gerhard,Schurz, Klaus,Fischer, Gerd
, p. 1468 - 1474 (2007/10/02)
Benzophenone Ph2C=O is able to "store" the silaethene Me2Si=C(SiMe3)2 (1), produced from Me2SiX-CLi(SiMe3)2 (X = F, Br, Ph2PO4), under formation of a cycloadduct (2b).At about 100 deg C, 2b by way of 1 transfers into the cycloadduct of 1 and Ph2C=O (3b), which in the course of transformation decomposes visibly (in the absence of Me3SiCl) or only by traces (in the presence of Me3SiCl) to secondary products.In the presence of ROH (R = H, Me, tBu, MeCO) or PhN=NSiMe3 or RN3 (R = tBu, Me3Si) or 2,3-dimethylbutadiene (dmb) about 100 deg C 2b and 3b form by way of 1 insertion products of 1 into the OH bond of ROH or a cycloadduct of 1 and PhN=NSiMe3 or cycloadducts of 1 and RN3 or cycloadduct and an ene reaction product of 1 and dmb.The rate constants/half lives of the first order transformation of 2b into 3b or of the first order decomposition of 2b or of 3b in the presence of reactive traps for 1 (ROH, Me3SiN3; benzene as solvent) are in the order of 0.3E-4 s-1/τ1/2 = 7 h (2b --> 3b; 90 deg C) 3E-4 s-1/τ1/2 = 3/4 h (2b + traps; 90 deg C), 0.4E-4 s-1/τ1/2 = 5 h (3b + traps, 110 deg C). - Keywords: Silaethene Me2Si=C(SiMe3)2, Insertions, Cycloadditions, Kinetic Studies
Storing of the Labile Silaethene Me2Si=C(SiMe3)2 with N-Trimethylsilyl-benzophenoneimine Ph2C=NSiMe3
Wiberg, Nils,Preiner, G.,Wagner, G.,Koepf, H.,Fischer, G.
, p. 1055 - 1061 (2007/10/02)
N-Trimethylsilyl-benzophenoneimine Ph2C=NSiMe3 is able to "store" the silaethene Me2Si=C(SiMe3)2 (1), produced from Me2SiF-CLi(SiMe3)2, under formation of a - and -cycloadduct (2, 3), respectively.Above 60 deg C (above 120 deg C) 2 or 3 by the way of 1 transform into 1:5 mixture of 2 and 3 (into a 1:1 mixture of the dimer of 1 and the insertion product of 1 into the SiN-bond of Ph2C=NSiMe3).In the presence of 2,3-dimethyl-1,3-butadiene (dmb), 2 or 3 form by way of the reaction of the intermediate 1 with dmb a -cycloadduct (75percent) and an ene reaction product (25percent).The rate constants of the first order decomposition of 2 or 3 in the presence of dmb (80 deg C, solvents like Et2O, C6H6) are in the order of 2 E-4 s-1 (τ1/2 ca. 1 h) and 3 E-5 s-1 (τ1/2 ca. 6 h), respectively. - Key words: Silaethene Me2Si=C(SiMe3)2, Ph2C=NSiMe3-adduct, Kinetic Studies
Reaktivitaet des Silaethens Me2Si=C(SiMe3)2: Thermolyse von (Me3Si)2(Me2XSi)CLi (X z. B. (PhO)2PO2) in Anwesenheit von Silaethen-Faengern
Wiberg, Nils,Preiner, Gerhard,Schieda, Oswald
, p. 3518 - 3532 (2007/10/02)
Silaethene Me2Si=C(SiMe3)2 (1), generated as a reaction intermediate by the thermal elimination of LiX from Me2XSi-CLi(SiMe3)2, combines with the reactants a - b (e. g.Me3Si-Cl, Me3Si-OMe) with insertion in the a - b bond, with a = b - c - H (e. g.CH2=CMe
