Dual-Hydrogen-Bond Donor and Brønsted Acid Cocatalysis Enables Highly Enantioselective Protio-Semipinacol Rearrangement Reactions
作者:Melanie A. S. Blackburn、Corin C. Wagen、M. Raul Bodrogean、Pamela M. Tadross、Andrew J. Bendelsmith、Dennis A. Kutateladze、Eric N. Jacobsen
DOI:10.1021/jacs.3c02960
日期:2023.7.19
A catalytic protio-semipinacol ring-expansion reaction has been developed for the highly enantioselective conversion of tertiary vinylic cyclopropyl alcohols into cyclobutanone products bearing α-quaternary stereogenic centers. The method relies on the cocatalytic effect of a chiral dual-hydrogen-bond donor (HBD) with hydrogen chloride. Experimental evidence is provided for a stepwise mechanism where
开发了一种催化原硫代半频那醇扩环反应,用于将叔乙烯环丙醇高度对映选择性转化为带有α-季立构中心的环丁酮产品。该方法依赖于手性双氢键供体(HBD)与氯化氢的共催化作用。实验证据证明了一种逐步机制,其中烯烃的质子化产生短寿命的高能碳正离子,随后进行 C-C 键迁移以产生对映体富集的产物。该研究将强酸/手性HBD共催化应用于弱碱性烯烃底物,为进一步研究涉及高能阳离子中间体的对映选择性反应奠定了基础。