Observations on the geometry of hydrogen transfer in [1,5] sigmatropic rearrangements
作者:H. Kwart、M. W. Brechbiel、R. M. Acheson、D. C. Ward
DOI:10.1021/ja00381a026
日期:1982.8
undertaken with the objective of identifying a (1,5) sigmatropic rearrangement occurring in a cyclic system which is not capable of such distention of the ..pi.. framework. The case for study was the rearrangement of the 9aH-quinolizine to the 4H-quinolizine. The temperature dependence of the isotope effect was again applied as the criterion of TS/sup + +/ geometry in H transfer. It has frequently been demonstrated
本研究的目的是确定在循环系统中发生的 (1,5) sigmatropic 重排,该系统无法扩展 ..pi.. 框架。研究案例是 9aH-喹嗪重排为 4H-喹嗪。同位素效应的温度依赖性再次用作 H 转移中 TS/sup + +/ 几何形状的标准。经常证明,虽然不能直接从同位素效应的传统过渡态理论(目前)推导出来,弯曲的 TS/sup + +/,即涉及 H 以锐角转移的一个,可以与与温度无关的 k/sub H//k/sub D/。也就是说,(..delta..E/sub a/)/sup H//sub D/ 的同位素效应参数的发现大约为 = 0 和 A/sub H//A/sub D/>>1。