Hypervalent Iodine(III)-Mediated Umpolung Dialkoxylation of N-Substituted Indoles

Herein, we report dialkoxylation of N-substituted indoles through a hypervalent iodine-mediated umpolung strategy, affording trans-2,3-dimethox-yindolines with up to 95% yield. In addition, C5-selective bromination of 2,3-dialkoxyindoline via NBS-mediated rearomatization was achieved. DFT calculation of the sequence of electrophilic addition and nucleophilic substitution pathway of N-substituted indoles has also been investigated.

Automated summary

In this study, we report a hypervalent iodine-mediated umpolung strategy for the dialkoxylation of N-substituted indoles, resulting in the formation of trans-2,3-dimethoxyindolines with up to 95% yield. We also achieved C5-selective bromination of 2,3-dialkoxyindoline via NBS-mediated rearomatization. Additionally, DFT calculation was used to study the sequence of electrophilic addition and nucleophilic substitution pathway of N-substituted indoles.