Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2010 Aug 18;132(32):11027-9. doi: 10.1021/ja105148g.
A nickel-catalyzed stereoconvergent method for the enantioselective Suzuki arylation of racemic alpha-chloroamides has been developed. This process provides a unique example of an asymmetric arylation of an alpha-haloamide, an enantioselective arylation of an alpha-chlorocarbonyl compound, and an asymmetric Suzuki reaction with an activated alkyl electrophile or an arylboron reagent. The method is also applicable to the corresponding enantioselective cross-coupling of alpha-bromoamides. The coupling products can be transformed without racemization into enantioenriched alpha-arylcarboxylic acids and primary alcohols. A modest kinetic resolution of the alpha-chloroamide was observed; a mechanistic study indicated that the selectivity may reflect discrimination by the chiral catalyst of the two enantiomeric alpha-chloroamides in an irreversible oxidative-addition process.
已开发出一种镍催化的对映选择性Suzuki 芳基化反应的对映体构型保持方法，用于外消旋的α-氯酰胺。该过程提供了一个不对称芳基化α-卤酰胺的独特实例，对α-氯羰基化合物的对映选择性芳基化，以及不对称Suzuki 反应与活化的烷基亲电试剂或芳基硼试剂的反应。该方法也适用于相应的对映选择性交叉偶联α-溴酰胺。偶联产物可在不消旋的情况下转化为手性富集的α-芳基羧酸和伯醇。观察到α-氯酰胺的适度动力学拆分；一项机理研究表明，选择性可能反映了手性催化剂在不可逆的氧化加成过程中对两种对映体α-氯酰胺的区分。
