Capricious Stereoselectivities of Alkenylpotassium Formation under Kinetic and Thermodynamic Control Oxygen-Triggered Configurational Equilibration of an Allyl Type Organometallic Compound
作者:Manfred Stähle、Jürgen Hartmann、Manfred Schlosser
DOI:10.1002/hlca.19770600527
日期:1977.7.13
(E)-isomers, no matter in which configuration the resulting organometallic is thermodynamically more stable. A striking illustration is given by (Z)-4,4-dimethyl-2-pentenyl potassium which is formed 15 times faster than its (E)-isomer, although the latter is clearly favored under equilibrium conditions. The configurational reorganization of alkenylpotassium compounds in tetrahydrofuran solution is very
(Z)-1-烷基化的丙烯在烯丙基部位的金属化反应比其(E)-异构体更快,无论在哪种构型下所得的有机金属在热力学上都更稳定。(Z)-4,4-二甲基-2-戊烯基钾给出了一个惊人的例证,其形成比其(E)-异构体快15倍,尽管后者在平衡条件下显然是有利的。烯基钾化合物在四氢呋喃溶液中的构型重组非常缓慢。然而,至少在一种情况下,微量的氧有效催化Z / E平衡。