119258-53-6Relevant academic research and scientific papers
Nucleophile-assisted racemisation of halosilanes; an alternative pathway involving halide exchange
Bassindale, Alan R.,Lau, Juliana C.-Y.,Taylor, Peter G.
, p. 213 - 224 (1988)
An NMR method using diastereotopic halosilanes, PhCH(Me)SiMe2X (X = Cl or Br) has been developed for studying nucleophile-assisted racemisations of halosilanes.A mechanism for racemisation involving halide exchange is proposed to account for the observati
Nucleophile-assisted racemisations of halosilanes - kinetic studies
Bassindale, Alan R.,Lau, Juliana C.-Y.,Taylor, Peter G.
, p. 75 - 82 (2007/10/02)
Kinetic studies have been carried out on the nucleophile-induced racemisation of PhMeCHSiMe2X, 2, X = triflate, Br or Cl.Thirteen nucleophiles were studied.The results are interpreted in terms of two competing mechanisms for racemisation: (a) nucleophile attack on a silane-nucleophile complex formed by displacement of the halide by the nucleophile, and (b) halide-halosilane exchange, with inversion of configuration.Solvent effects were examined, and kinetic orders in the nucleophile and in one case for the halosilane were determined.The order in added nucleophile varied between one and two, with strong nucleophiles in polar media.Anomalously high orders in nucleophile were observed in non-polar media and are ascribed to aggregation of the nucleophile.A kinetic analysis of the competing mechanisms was attempted, and was consistent with the experimental findings.In this particular series of reactions involving compounds with good leaving groups and relatively powerful nucleophiles there was no evidence for intermediates involving extracoordinate silicon. Keywords: Silicon; Racemisation; Mechanism
