Blackmond Donna G, Hodnett Neil S, Lloyd-Jones Guy C
Department of Chemistry, Imperial College, London SW7 2AZ, UK.
J Am Chem Soc. 2006 Jun 14;128(23):7450-1. doi: 10.1021/ja062173f.
This work provides simulations as well as experimental results from kinetic resolutions to demonstrate that a constant product enantioselectivity versus conversion profile in kinetic resolution is not a general consequence of pseudo zero order kinetics in [substrate] but occurs only under specific mechanistic constraints. For such a profile to be observed, the reaction must follow a mechanism exhibiting saturation kinetics for only one enantiomeric [substrate] on the only one of the two parallel pathways. For a single catalyst species, this will be limited to situations of near-perfect selectivity. Combining kinetic profiles with the enantioselectivity/conversion relationship in kinetic resolution can help to distinguish between proposed mechanisms and provide information about relative binding constants, the reactivity of intermediate species, and turnover by more than one active catalyst species.
这项工作提供了动力学拆分的模拟以及实验结果,以证明动力学拆分中产物对映体选择性与转化率的恒定关系并非底物浓度呈准零级动力学的普遍结果,而是仅在特定的机理限制下才会出现。要观察到这样的关系,反应必须遵循一种机理,即在两条平行途径中的仅一条上,仅对一种对映体底物表现出饱和动力学。对于单一催化剂物种而言,这将仅限于接近完美选择性的情况。将动力学曲线与动力学拆分中的对映体选择性/转化率关系相结合,有助于区分所提出的机理,并提供有关相对结合常数、中间物种的反应性以及多种活性催化剂物种的周转情况的信息。