Enantioselective Acetalization by Dynamic Kinetic Resolution for the Synthesis of γ‐Alkoxybutenolides by Thiourea/Quaternary Ammonium Salt Catalysts: Application to Strigolactones
作者:Motohiro Yasui、Ayano Yamada、Chihiro Tsukano、Andrea Hamza、Imre Pápai、Yoshiji Takemoto
DOI:10.1002/ange.202002129
日期:2020.8.3
synthesis, intermolecular asymmetric acetalization remains an unsolved problem. In this study, a thiourea‐ammonium hybrid catalyst was shown to promote the O‐alkylation of enols with a racemic γ‐chlorobutenolide through dynamic kinetic resolution to give chiral acetals with good enantioselectivity. The catalyst simultaneously activates both the nucleophile and electrophile in a multifunctional manner. This
摘要尽管缩醛化是有机合成中的一个基本转化,但分子间不对称缩醛化仍然是一个未解决的问题。在这项研究中,硫脲-铵杂化催化剂被证明可以通过动态动力学拆分促进烯醇与外消旋γ-氯丁烯内酯的O-烷基化,从而得到具有良好对映选择性的手性缩醛。该催化剂以多功能方式同时激活亲核试剂和亲电试剂。该方法应用于多种独脚金内酯的不对称合成。DFT 计算表明,γ-氯丁烯内酯的氯原子与催化剂的甲苯磺酰胺氢原子之间的氢键相互作用,以及其他类型的非共价催化剂-底物相互作用,对于实现高立体选择性至关重要。