2-Hydroxy-3-(Pyrrolidin-1-yl)-Indolines: A Platform for Accessing Decorated Deaminokynurenines Enabled by a Double Tautomeric Control

In this study we introduce indoline hemiaminals as phenacyl bromide surrogates for the synthesis of deaminokynurenine derivatives through cyclic-linear tautomeric intermediates. The reaction proceeds through a tandem process involving the ring opening of indoline hemiaminals, generating transient acyclic aldehydes which are then trapped with in situ generated enolate species. Our protocol overcomes traditional dilemma in production of polar-mismatch 1,4-dicarbonyl compounds by utilizing a transient highly electrophilic linear aldehyde and late-stage transposition of carbonyl moiety. The synthetic utility of our transformation was demonstrated by follow-up transformations, including the first total synthesis of quinoline-2,4-dione alkaloid.

This is the peer reviewed version of the following article: [K. Tokushige, T. Abe*, Asian Journal of Organic Chemistry. 2025, 00. https://doi.org/10.1002/ajoc.202500439], which has been published in final form at [https://doi.org/10.1002/ajoc.202500439]. 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 thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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