Catalytic Asymmetric Synthesis of Vicinal Quaternary Stereocenters Enabled by Alkylation of α,α-Disubstituted Aldehydes with 3-Bromooxindoles
作者:Long-Jun Dong、Qi Wang、Jing-Feng Zhang、Zhen Li、Dao-Yong Zhu、Xiao-Ming Zhang、Yong-Qiang Tu、Shao-Hua Wang
DOI:10.1021/acs.orglett.4c00700
日期:2024.4.19
An organocatalytic enantioselective alkylation of α,α-disubstituted aldehydes with 3-bromooxindoles is reported. Enantioenriched oxindoles with vicinal quaternary stereocenters are accessed by an asymmetric conjugate addition process of branched aldehydes with o-azaxylylene intermediates (indol-2-ones). Key to the success of highly diastereo- and enantioselective transformations is the combined use
报道了 α,α-二取代醛与 3-溴氧吲哚的有机催化对映选择性烷基化。通过支链醛与邻氮二甲苯中间体(吲哚-2-酮)的不对称共轭加成过程获得具有邻位季立体中心的对映体富集的羟吲哚。高度非对映选择性和对映选择性转化成功的关键是联合使用源自螺吡咯烷支架的三苯基甲硅烷基保护的β-氨基醇催化剂和3,5-二硝基苯甲酸。这项研究还提出了醛烷基化形成连续四元立构中心的罕见例子。