Indole Editing Enabled by HFIP‐Mediated Ring‐Switch Reactions of 3‐Amino‐2‐Hydroxyindolines

We found the novel reactivity of hemiaminal as a precursor for indole editing at the multi-site. The HFIP-promoted indole editing of indoline hemiaminals affords 2-arylindoles through a ring-switch sequence. The key to success of this transformation is to use a cyclic hemiaminal as an a-amino aldehyde surrogate under transient tautomeric control. This transformation features mild reaction conditions and good yields with broad functional group tolerance. The utility of this transformation is presented through the one-pot protocol and the synthesis of isocryptolepine.

This is the peer reviewed version of the following article: [T. Abe, T. Yamashiro, K. Shimizu, D. Sawada, Chem. Eur. J. 2022, 28, e202201113.], which has been published in final form at [https://doi.org/10.1002/chem.202201113]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages there of by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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