Dynamic Kinetic Asymmetric Cross-Benzoin Additions of β-Stereogenic α-Keto Esters
作者:C. Guy Goodman、Jeffrey S. Johnson
DOI:10.1021/ja508521a
日期:2014.10.22
The dynamic kinetic resolution of β-halo α-keto esters via an asymmetric cross-benzoin reaction is described. A chiral N-heterocyclic carbene catalyzes the umpolung addition of aldehydes to racemic α-keto esters. The resulting fully substituted β-halo glycolic ester products are obtained with high levels of enantio- and diastereocontrol. The high chemoselectivity observed is a result of greater electrophilicity
描述了通过不对称交叉安息香反应对 β-卤代 α-酮酯进行动态动力学拆分。手性 N-杂环卡宾催化醛与外消旋 α-酮酯的 umpolung 加成。得到的完全取代的 β-卤代乙醇酸酯产品具有高水平的对映和非对映控制。观察到的高化学选择性是由于 α-酮酯对 Breslow 中间体具有更大的亲电性。反应产物显示出经过高度非对映选择性底物控制的还原,得到高度官能化的立体三联体。