Asymmetric Catalytic (3 + 2) Cyclization and Sequential Reaction to Construct Dihydrofuran- and Azepine-Based Spirooxindoles

作者：Qiliang Luo, Yuqiao Zhou, Jing Zhang, Shunxi Dong, Xiaoming Feng · 发表于：Organic Letters · 年份：2025 · DOI：10.1021/acs.orglett.5c00182 · 被引用次数：6 · 研究领域：Asymmetric Synthesis and Catalysis、Synthetic Organic Chemistry Methods、Catalytic C–H Functionalization Methods

The enantioselective formal (3 + 2) cyclization and sequential reaction of 2-malononitrile-substituted oxindoles with benzaldehydes and ortho -aminobenzaldehydes were achieved by chiral N,N ′-dioxide/metal complex Lewis acid catalysts. This protocol supplies facile and efficient access to highly functionalized chiral dihydrofuran- and azepine-based spirooxindoles. Based on the control experiments and the deuterium labeling studies, the interconversion of (3 + 2) diastereomeric intermediates under the reaction conditions and reversible 1,5-H transfer step were disclosed.