Unlocking the Latent Dienophile Reactivity of Neutral Ketimines through Ketimine–Enamine Tautomerism: A Diastereoselective Povarov Reaction between Two Neutral Imines
Abstract Herein, we report a copper-catalyzed Povarov reaction between two neutral imines enabled by the latent dienophile reactivity of ketimines. In situ-generated endocyclic enamines from benzo[b][1,4]oxazines undergo cycloaddition with aldimine-derived aza-dienes at room temperature, affording fused tetrahydroquinolines bearing a C4 quaternary stereocenter in good to excellent yields with complete diastereoselectivity. Aromatic and aliphatic aldimines are well tolerated. DFT studies support an inverse-electron-demand Diels–Alder mechanism, revealing an unusual reactivity paradigm enabled by ketimine-enamine tautomerism.
Authors
- Koushik Naskar (ORCID: https://orcid.org/0009-0007-1588-344X)
- Imtiaj Mondal (ORCID: https://orcid.org/0009-0007-4186-2044)
- Sudip Karmakar (ORCID: https://orcid.org/0009-0003-8687-2351)
- Indubhusan Deb (ORCID: https://orcid.org/0000-0002-9007-1042)
- Kushal Chowdhury
Institutions
- Indian Institute of Chemical Biology (IN)
- Academy of Scientific and Innovative Research (IN)
Publication Details
- Journal
- Organic Letters
- Published
- 2026-09-09
- DOI
- https://doi.org/10.1021/acs.orglett.6c03561
- Primary Topic
- Asymmetric Synthesis and Catalysis
- Type
- article
- Field-Weighted Citation Impact
- 0.00