Oxygen exchange in 2-butanol and hydration of 1-butene do not proceed through a common carbocation intermediate
作者:Paul E. Dietze、William P. Jencks
DOI:10.1021/ja00241a024
日期:1987.4
transfer is also significant in this reaction. Comparison of the product yields from 1-butene and the rate constants for isomerization and oxygen exchange of (4-/sup 14/C)-2-butanol in the earlier work shows that the two reactions do not occur through a common carbocation intermediate. The preferential formation of cis-2-butene from 1-butene and trans-2-butene from 2-butanol confirms this conclusion
酸催化的 1,1,1,2,3,3- 1-位和 4-位之间的 1,1,1,2,3,3- 六氘化 2-丁醇的 4-甲基异构化发生得比脱水成 2-丁烯更快,如通过氢掺入测量从水变成 2-丁醇的 3 位。这些过程的速率常数分别为 k/sub isom/ = 1.1 x 10/sup -6/ s/sup -1/ 和 k/sub hyd/ = 5.6 x 10/sup -7/ s/sup -1/ , 在 0.55 M HClO/sub 4/ 在 100/sup 0/C。这些结果要求通过氢化物从 C-3 转移到 C-2 以及通过 2-丁烯的形成和水合发生异构化。在 (4-/sup 14/C)-1-丁烯的酸催化水合中,异构化产物的初始产率为 6%,之后 2-丁烯显着积累(Manassen, J.;Klein, FJ Chem. Soc . 1960, 4023),表明氢化物转移在该反应中也很重要。早期工作中