作者:Xavier Creary、Elizabeth D. Kochly
DOI:10.1021/jo802722z
日期:2009.3.6
intermediate cyclopropyl cation undergoes substantial ring opening since β-silyl stabilization is not large (calculated stabilization energy of 12 kcal/mol). Solvolysis rates of 2-trimethylsilylbenzocyclobutyl derivatives are not significantly enhanced by the β-trimethylsilyl group. β-Silyl stabilization of benzocyclobutenyl carbocations generated in solution has been effectively eliminated due to antiaromatic
1-(三甲基甲硅烷基甲基)环丙基甲磺酸酯在CD 3 CO 2 D中的溶剂分解产生开环产物以及亚甲基环丙烷。由于β-三甲基甲硅烷基而引起的速率提高是约10 6。β-甲硅烷基对中间阳离子的大的稳定作用(可能导致速率提高高达10 12)已被抑制。B3LYP / 6-31G *计算研究表明,碳正离子稳定能为16.6 kcal / mol。1-苯基-2-三甲基甲硅烷基环丙基氯的溶剂分解速率提高了10 3 -10 4倍。由于β-甲硅烷基的稳定度不大(计算得出的稳定能为12 kcal / mol),因此中间环丙基阳离子会发生大量开环。β-三甲基甲硅烷基基团不会显着提高2-三甲基甲硅烷基苯并环丁基衍生物的溶剂分解速率。出于抗芳香性考虑(当R = Ph时,计算的稳定能为3.7 kcal / mol),已有效消除了溶液中生成的苯并环丁烯基碳正离子的β-甲硅烷基稳定作用。虽然计算研究与溶剂分解速率研究平行,但它