Enantioselective Synthesis of <i>N</i>
,<i>S</i>
-Acetals by an Oxidative Pummerer-Type Transformation using Phase-Transfer Catalysis
作者:Souvagya Biswas、Koji Kubota、Manuel Orlandi、Mathias Turberg、Dillon H. Miles、Matthew S. Sigman、F. Dean Toste
DOI:10.1002/anie.201711277
日期:2018.1.8
Deuterium‐labelling experiments were performed to identify the stereodiscrimination step of this process. Further analysis of the reaction transition states, by means of multidimensional correlations and DFT calculations, highlight the existence of a set of weak noncovalent interactions between the catalyst and substrate that govern the enantioselectivity of the reaction.
据报道,这是首次使用相转移催化的对映体选择性氧化氧化Pummerer型转化,以提供对映体富集的含硫杂环。该反应包括将硫化物直接氧化成硫鎓中间体,然后进行不对称分子内亲核加成反应,形成具有中等至高对映体选择性的手性环状N,S-缩醛。进行氘标记实验以鉴定该过程的立体鉴别步骤。通过多维相关和DFT计算对反应过渡态进行进一步分析,突出了催化剂与底物之间存在一组弱的非共价相互作用,这些相互作用决定了反应的对映选择性。