Dynamic kinetic resolution via asymmetric conjugate reduction: Enantio- and diastereoselective synthesis of 2,4-dialkyl cyclopentanones
Dynamic kinetic resolution via asymmetric conjugate reduction: Enantio- and diastereoselective synthesis of 2,4-dialkyl cyclopentanones
复制标题
DOI：
10.1021/ja025603k
复制
发表时间：
2002-03-27
影响因子：
15
通讯作者：
Buchwald, SL
中科院分区：
文献类型：
--
作者：
Jurkauskas, V;Buchwald, SL
本文报道了外消旋3，5-二烷基-2-环戊烯-1-酮的动力学和动力学拆分。动力学拆分，具有良好的选择性因子（25−52），通过共轭还原与催化CuCl/NaOt-Bu/（S）-p-tol-BINAP和化学计量的聚（甲基氢硅氧烷）（PMHS）。当在反应混合物中包括化学计量量的NaOt-Bu和t-BuOH时，发生起始材料的快速外消旋化，允许环戊烯酮底物的动态动力学拆分。该方法以较高的立体选择性（ee ≥ 91%，dr ≥ 90：10）和较高的收率（≥89%）分离了手性2，4-二烷基环戊酮。
Herein, we report the kinetic and the dynamic kinetic resolutions of racemic 3,5-dialkyl-2-cyclopenten-1-ones. Kinetic resolution, with good selectivity factors (25−52), was achieved by conjugate reduction with catalytic CuCl/NaOt-Bu/(S)-p-tol-BINAP and stoichiometric quantities of poly(methylhydrosiloxane) (PMHS). When stoichiometric amounts of NaOt-Bu andt-BuOH were included in the reaction mixture, rapid racemization of the starting material occurred allowing for the dynamic kinetic resolution of the cyclopentenone substrates. In this process, chiral 2,4-dialkylcyclopentanones were isolated with high stereoselectivity (ee ≥ 91%, dr ≥ 90:10) and in high yield (≥89%).