Phosphoryl-transfer reactions of phosphodiesters: characterization of transition states by heavy-atom isotope effects
作者:Alvan C. Hengge、W. W. Cleland
DOI:10.1021/ja00015a043
日期:1991.7
measures changes in transition state bonding to the nonbridge oxygen atoms in the central phosphoryl group in these S N 2 reactions. The 15 N isotope effects measure transition-state bond cleavage to the leaving group p-nitrophenol. The isotope effect data indicate that weaker nucleophiles lead to a more associative transition state with respect to the central phosphoryl group (decreased bonding to
已经测量了磷酸二酯 3,3-二甲基丁基对硝基苯基磷酸酯在酸和碱水解、β-环糊精裂解和蛇毒磷酸二酯酶裂解条件下的磷酰基转移反应的次级 18 O 和 15 N 同位素效应。同位素标记和其他实验表明,这些反应通过 SN 2(P) 机制进行。次级 18 O 同位素效应测量在这些 SN 2 反应中与中心磷酰基中的非桥氧原子结合的过渡态的变化。15 N 同位素效应测量到离去基团对硝基苯酚的过渡态键断裂。