Wang Kun, Zhang Lin, Tang Weijun, Sun Huaming, Xue Dong, Lei Ming, Xiao Jianliang, Wang Chao
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China.
State Key Laboratory of Chemical Resource Engineering, Institute of Computational Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China.
Angew Chem Int Ed Engl. 2020 Jul 6;59(28):11408-11415. doi: 10.1002/anie.202003104. Epub 2020 May 18.
The first example of an asymmetric Guerbet reaction has been developed. Using commercially available, classic Noyori Ru -diamine-diphosphine catalysts, well-known in asymmetric hydrogenation, racemic secondary alcohols are shown to couple with primary alcohols in the presence of a base, affording new chiral alcohols with enantiomeric ratios of up to 99:1. Requiring no reducing agents, the protocol provides an easy, alternative route for the synthesis of chiral alcohols. Mechanistic studies reveal that the reaction proceeds via a Ru-catalyzed asymmetric hydrogen autotransfer process in concert with a base-promoted allylic alcohol isomerization.
不对称盖布瑞尔反应的首个实例已被开发出来。使用市售的、经典的用于不对称氢化反应的诺伊里钌-二胺-二膦催化剂，外消旋仲醇在碱的存在下与伯醇发生偶联反应，得到对映体比例高达99:1的新型手性醇。该方法无需还原剂，为手性醇的合成提供了一条简便的替代途径。机理研究表明，该反应通过钌催化的不对称氢自动转移过程与碱促进的烯丙醇异构化协同进行。
