Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany.
Nat Commun. 2017 Jun 1;8:15547. doi: 10.1038/ncomms15547.
The enantioselective silylation of racemic alcohols, where one enantiomer reacts faster than the other, is an alternative approach to established enzymatic and non-enzymatic acylation techniques. The existing art is either limited to structurally biased alcohols or requires elaborate catalysts. Simple substrates, such as benzylic and allylic alcohols, with no coordinating functionality in the proximity of the hydroxy group have been challenging in these kinetic resolutions. We report here the identification of a broadly applicable chiral catalyst for the enantioselective dehydrogenative coupling of alcohols and hydrosilanes with both the chiral ligand and the hydrosilane being commercially available. The efficiency of kinetic resolutions is characterized by the selectivity factor, that is, the ratio of the reaction rates of the fast-reacting over the slow-reacting enantiomer. The selectivity factors achieved with the new method are good for acyclic benzylic alcohols (≤170) and high for synthetically usefully cyclic benzylic (≤40.1) and allylic alcohols (≤159).
外消旋醇的对映选择性硅烷化，其中一种对映体比另一种反应更快，是对已建立的酶和非酶酰化技术的替代方法。现有技术要么仅限于结构偏向性醇，要么需要精心设计的催化剂。在这些动力学拆分中，简单的底物，如苄基和烯丙基醇，在羟基附近没有配位官能团，具有挑战性。我们在这里报告了一种广泛适用的手性催化剂的鉴定，用于醇和硅烷的对映选择性脱氢偶联，其中手性配体和硅烷都可商购获得。动力学拆分的效率由选择性因子来表征，即快速反应对映体与缓慢反应对映体的反应速率之比。新方法获得的选择性因子对于无环苄基醇（≤170）是良好的，对于合成有用的环状苄基（≤40.1）和烯丙基醇（≤159）是高的。
