1,3-Hydron transfer in some 5- and 7-substituted 1-methylindenes. Enantioselectivities and enantiomer-dependent kinetic isotope effects
作者:Marie Aune、G�ran Bergson、Olle Matsson
DOI:10.1002/poc.610080604
日期:1995.6
[5-methoxy- (2), 5-fluoro- (3), 5-nitro- (4) and 7-nitro (5)] and 1-methylindene (1) were employed as substrates. The rate constants, the enantioselectivities and the kinetic isotope effects (KIEs) for the enantioselective reactions [(kH/kD)+ and (kH/kD)−] were determined at 20°C using (+)-(8R, 9S)-dihydroquinidine as chiral catalyst in the solvent o-dichlorobenzene. The rate constants vary according to the
在茚体系中研究了碱催化的底物-对映选择性的1,3-氢转移(动力学拆分)。在芳香环中取代的一系列1-甲基茚[5-甲氧基-(2),5-氟-(3),5-硝基-(4)和7-硝基(5)]和1-甲基茚(1)被用作底物。对映选择性反应[(k H / k D)+和(k H / k D)- ]的速率常数,对映选择性和动力学同位素效应(KIEs)在20°C下使用(+)-(8 R,9 S)-二氢奎尼丁为溶剂o的手性催化剂-二氯苯。速率常数根据取代基的电子效应而变化。初级氘KIE范围从4·73 [对于(+)-(S)-2]到11·3 [对于(-)-(R)-5],与速率常数相关,如预期的那样Melander–Westheimer假设。在芳环中引入取代基降低了对映选择性。除了5中的所有化合物显示的对映选择性的同样的意义[ ķ + / ķ - > 1; 使用的所有底物均为(+)-(S)/(-)-(R)]。KIE的对映异构体依赖性在1