117984-22-2Relevant academic research and scientific papers
Generation and Detection of the Silaethene Ph2Si=C(SiMe3)2
Wiberg, Nils,Link, Matthias,Fischer, Gerd
, p. 409 - 418 (2007/10/02)
Bromotrisilylmethanes (Me3Si)2(Ph2XSi)CBr (4-13; Table 1) are formed by the reaction of (Me3Si)2(Ph2HSi)CM (M = Li, Na) with bromine or with bromine/chlorine (X = H, Cl, Br) and also by treating (Me3Si)2(Ph2BrSi)CBr with KHF2 (X = F), H2O or MeOH (X = OH, OMe), MeLi (X = Me), BuLi/Br2 (X = Bu), PhLi/Br2 or PhLi/PhOLi/Br2 (X = Ph, OPh).PhLi, BuLi, and tBu3SiNa convert the bromotrisilylmethanes by Br/M exchange into compounds (Me3Si)2(Ph2XSi)CM, which may be protolyzed, alkylated, and brominated .For X = halogen the equilibrium (Me3Si)2(Ph2XSi)CM Ph2Si=C(SiMe3)2 (3) + MX exists.Thereby, silaethene 3 is formed in Et2O at -78 deg C (X/M = Br/Li) or at room temperature (X/M = F/Li, Br/Na), respectively, reversibly in low concentrations and at higher temperatures irreversibly (formation of secondary products of 3).The intermediacy of 3 has been established chemically by trapping 3 with (for example) RLi (formation of insertion products in the R-Li bond), Ph2C=NSiMe3 (formation of a cycloadduct, which may serve as a source of 3), tBu2MeSiN3 (formation of a cycloadduct), and particularly 2,3-dimethyl-1,3-butadiene (formation of Diels-Alder and ene reaction products).In the last case products and yields are independent of the origin of 3.From Me2Si=C(SiMe3)2 (1) to 3 there is only a gradual (but no principal) change of silaethene reactivity (3 is more Lewis acidic than 1). - Keywords: Silaethenes/ Bromotris(silyl)methane derivatives
