Resonance Effects in the Solvolysis of<i>α</i>-<i>t</i>-Butyl-<i>α</i>-neopentylbenzyl and<i>α</i>-<i>t</i>-Butyl-<i>α</i>-isopropylbenzyl<i>p</i>-Nitrobenzoates
作者:Mizue Fujio、Makoto Ohe、Kazuhide Nakata、Yutaka Tsuji、Masaaki Mishima、Yuho Tsuno
DOI:10.1246/bcsj.70.929
日期:1997.4
Substituent effects on the solvolysis rates of α-t-butyl-α-neopentylbenzyl and α-t-butyl-α-isopropylbenzyl p-nitrobenzoates in 50% (v/v) aqueous EtOH at 75 °C were correlated with the Yukawa–Tsuno equation to give ρ = −3.37 and r = 0.78, and ρ = −3.09 and r = 0.68, respectively. The reduction in r values from r = 1.00 characteristic of full conjugation is ascribed to deviation from coplanarity of the
取代基对 α-叔丁基-α-新戊基苄基和 α-叔丁基-α-异丙基苄基对硝基苯甲酸酯在 75°C 的 50% (v/v) 乙醇水溶液中的溶剂分解速率的影响与 Yukawa-Tsuno 相关等式分别给出 ρ = -3.37 和 r = 0.78,以及 ρ = -3.09 和 r = 0.68。r 值从 r = 1.00 的完全共轭特征的减少归因于碳阳离子中心和过渡态苄基 π 系统的共面性的偏差。对于一系列空间位阻叔二烷基苄基溶剂分解,根据关系 r/rmax = cos2 θ 估计出共面性扭曲的扭转角。为这些扭曲的苄基系统指定的扭转角与理论计算的相应 6-31G* 优化碳鎓离子的二面角非常一致。