Silicon Effects. VI.<i>β</i>-Silicon Effect of Various Silyl Groups in Solvolysis for<i>α</i>-Alkylbenzyl and<i>α</i>-Silybenzyl Systems
作者:Nobujiro Shimizu、Sin-ichiro Watanabe、Fumie Hayakawa、Sigefumi Yasuhara、Yuho Tsuno、Takahiko Inazu
DOI:10.1246/bcsj.67.500
日期:1994.2
The kinetic β-silicon effects of various silyl groups including Me3Si, Me3SiMe2Si, (C6H5)Me2Si, (i-PrO)Me2Si, and (CH3OCH2)Me2Si were measured in kc solvolysis of two different benzylic systems of the types, ArCH(OCOCF3)CH2R (3: Ar = phenyl or 3,5-dichlorophenyl, R = silyl group) and C6H5CH(Cl)SiMe2R (4: R = silyl group). The relative β-silyl accelerations were 1.0 : 5.57 : 0.309 for R = Me3Si; Me3SiMe2Si
包括 Me3Si、Me3SiMe2Si、(C6H5)Me2Si、(i-PrO)Me2Si 和 (CH3OCH2)Me2Si 在内的各种甲硅烷基的动力学 β-硅效应在两种不同类型的苄基体系 ArCH(OCOCF3) 的 kc 溶剂分解中测量CH2R(3:Ar = 苯基或 3,5-二氯苯基,R = 甲硅烷基)和 C6H5CH(Cl)SiMe2R(4:R = 甲硅烷基)。对于 R = Me3Si,相对 β-甲硅烷基加速度为 1.0 : 5.57 : 0.309;对于系统 3,分别为 Me3SiMe2Si 和 (C6H5)Me2Si,对于系统 4,R = Me3Si、Me3SiMe2Si、(i-PrO)Me2Si 和 (CH3OCH2)Me2Si 分别为 1.0:7.65:0.502:0.289。 β-硅效应随γ-取代基的变化被解释为反映了β-C-Si 和β-Si-Si σ-键超共轭能力的变化,主要是由于γ-取代基的诱导作用。