Transition-State Charge Stabilization through Multiple Non-covalent Interactions in the Guanidinium-Catalyzed Enantioselective Claisen Rearrangement
作者:Christopher Uyeda、Eric N. Jacobsen
DOI:10.1021/ja110842s
日期:2011.4.6
mechanism by which chiral arylpyrrole-substituted guanidinium ions promote the Claisen rearrangement of O-allyl α-ketoesters and induce enantioselectivity was investigated by experimental and computational methods. In addition to stabilization of the developing negative charge on the oxallyl fragment of the rearrangement transition state by hydrogen-bond donation, evidence was obtained for a secondary
通过实验和计算方法研究了手性芳基吡咯取代的胍离子促进 O-烯丙基α-酮酯的克莱森重排和诱导对映选择性的机制。除了通过氢键捐赠稳定重排过渡态的草烯基片段上正在发展的负电荷外,还获得了催化剂芳香取代基的 π 系统与阳离子烯丙基片段之间的二次吸引相互作用的证据。根据该提议,在一系列取代的芳基吡咯衍生物中,观察到对映选择性发生可预测的变化。这种机理分析导致开发了一种新的对二甲氨基苯基取代的催化剂,