Incremental Solvation Precedes Ion-Pair Separation in Enantiomerization of a Cyano-Stabilized Grignard Reagent
作者:Neeraj N. Patwardhan、Ming Gao、Paul R. Carlier
DOI:10.1002/chem.201102253
日期:2011.10.24
Concerted or stepwise? Ion‐pair separation is often proposed as a mechanism for enantiomerization of organolithium reagents in ethereal solvents. But what is the timing of the solvation and bond‐cleavage events? Are they concerted, or does one precede the other? Reaction order and Eyring studies of Grignard 1 in Et2O/toluene mixtures clearly demonstrate addition of solvent occurs before rupture of
一致还是分步进行?通常建议将离子对分离作为在醚溶剂中有机锂试剂对映异构化的机制。但是,溶剂化和键断裂事件的发生时间是什么?他们是齐心协力,还是一个先于另一个?反应顺序和格利雅的艾林研究1在Et 2 O /甲苯混合物清楚地证明加入溶剂发生之前所述Mg的破裂 C键。