CHEMISTRY OF ORGANOSILICON COMPOUNDS. CXXIII. NEW PHOTOCHEMICAL AND THERMAL DEGRADATION REACTIONS OF VINYLDISILANES TO VINYLSILANES THROUGH (η3-1-SILAPROPENYL)TRICARBONYLIRON COMPLEXES

Article abstract of DOI:10.1016/S0022-328X(00)94359-6

Vinyldisilanes (II) of the type R¹CH=CR²SiMe2SiMe3 (a, R¹ = Ph, R² = H; b, R¹ = H, R² = Me; c, R¹ = R² = H) and (R¹CH = CHSiMeR³-)2 (d, R¹ = Ph, R³ = Me; e, R¹ = H, R³ = Ph) undergo a novel degradation reaction to give the corresponding vinylsilanes, R¹CH = CR2SiMe3 and (R¹CH=CH)2SiMeR³, respectively, under photochemical or thermal conditions in the presence of a stoichiometric amount of pentacarbonyliron.Two α-styryldisilanes (IIf, CH2=CPhSiMe2SiMe3 and IIg, 2) undergo similar degradation reactions, but gave β-styryl- silanes.In the presence of additional benzophenone, IIb, IIc, and IIf gave (E)-Me3SiCH=CRSiMe2OCHPh2 (b, R = Me; c, R = H; f, R = Ph) under either photochemical or thermal conditions, but IIa gave under photochemical, or Ph2CHSiMe3 under thermal conditions as main product.Mechanisms involving η³-1-silapropenyltricarbonyliron intermediates are proposed, and indeed separately prepared (η³-1-silapropenyl)(trimethylsilyl)tricarbonyliron gave the same products under similar conditions.