Merck & Company, Inc., Merck Research Laboratories, Department of Process Research, P.O. Box 2000, Rahway, New Jersey 07065, USA.
Org Lett. 2010 Feb 5;12(3):512-5. doi: 10.1021/ol902715d.
Dynamic kinetic resolution (deracemization) of various alpha-alkyl-substituted beta-ketoamides 1 via asymmetric transfer hydrogenation proceeded efficiently to give the corresponding syn-beta-hydroxy amides 3 in high diastereo- and enantioselectivities. Specifically, subjection of 1 to HCO(2)H and Et(3)N in the presence of 0.5-1 mol % of pentafluorobenzenesulfonyl-DPEN-Ru catalyst 2b at 30-40 degrees C in either PhCH(3) or CH(2)Cl(2) generated the syn-hydroxy product 3 selectively in 15-33:1 dr, 93-97% ee, and 75-88% isolated yields.
通过不对称转移氢化对各种α-烷基取代的β-酮酰胺 1 进行动态动力学拆分(外消旋化),可有效地得到相应的顺式-β-羟基酰胺 3,具有很高的非对映选择性和对映选择性。具体而言,在 30-40°C 下,将 1 置于 HCO(2)H 和 Et(3)N 中,在 0.5-1mol%五氟苯磺酰基-DPEN-Ru 催化剂 2b 的存在下,在 PhCH(3)或 CH(2)Cl(2)中,以 15-33:1 的 dr、93-97%ee 和 75-88%的分离产率选择性地生成顺式-羟基产物 3。