NAD(P)<sup>+</sup>-NAD(P)H Models. 88. Stereoselection without Steric Effect but Controlled by Electronic Effect of a Carbonyl Group: Syn/Anti Reactivity Ratio, Kinetic Isotope Effect, and an Electron-Transfer Complex as a Reaction Intermediate
作者:Atsuyoshi Ohno、Yoshiteru Ishikawa、Norimasa Yamazaki、Mutsuo Okamura、Yasushi Kawai
DOI:10.1021/ja972804t
日期:1998.2.1
reactive than the corresponding syn hydrogen (deuterium). The syn/anti reactivity ratio depends on the reactivity of the quinone (stereoselection without steric effect). The initial electron-transfer process, which is associated with the weakening of the C4−H(D) bond, results in the formation of an electron-transfer complex prior to the chemical reaction. The isotope effect affecting this equilibrium constant
1,4,6,7-Tetrahydro-1,6,11-trimethyl-5-oxo-5H-benzo[c]pyrido[2,3-e]azepin (11Me-MMPAH) 及其 4-mono-和 4 ,4-二氘化类似物已被一系列对苯醌氧化。该化合物相对于羰基偶极子的取向具有轴向手性。4 位的氢(氘)对氧化具有不同的反应性:反(相对于羰基偶极子)氢的反应性是相应的合成氢(氘)的 3 到 32 倍。顺/反反应性比率取决于醌的反应性(没有空间效应的立体选择)。最初的电子转移过程与 C4-H(D) 键的减弱有关,导致在化学反应之前形成电子转移复合物。影响这个平衡常数的同位素效应是“产物同位素效应”的起源,长期以来一直是争论的话题。氧化中的动力学初级和次级同位素效应是...