Asymmetric Cyanosilylation of α-Keto Esters Catalyzed by the [Ru(phgly)<sub>2</sub>(binap)]-C<sub>6</sub>H<sub>5</sub>OLi System
作者:Nobuhito Kurono、Masato Uemura、Takeshi Ohkuma
DOI:10.1002/ejoc.200901501
日期:2010.3
The asymmetric reaction of α-keto esters and (CH 3 ) 3 SiCN, catalyzed by a combined system of [Ru(S)-phgly) 2 (S)-binap}] and C 6 H 5 OLi with a substrate-to-catalyst molar ratio (S/C) of 1000 at -60 °C, affords silylated cyanohydrins in up to 99 % ee. Cyanosilylation smoothly proceeds with an S/C of 10,000 at ―50 °C. The use of Xyl-Binap instead of Binap as a ligand provides better enantioselectivity
α-酮酯和 (CH 3 ) 3 SiCN 的不对称反应,由 [Ru(S)-phgly) 2 (S)-binap}] 和 C 6 H 5 OLi 的组合系统催化,底物-在 -60 °C 下,催化剂摩尔比 (S/C) 为 1000,可提供高达 99% ee 的甲硅烷基化氰醇。氰基硅烷化在 ―50 °C 下以 10,000 的 S/C 顺利进行。在某些情况下,使用 Xyl-Binap 代替 Binap 作为配体可提供更好的对映选择性。一系列芳香族、杂芳香族、脂肪族和 α,β-不饱和酮酯被转化为所需的产物。