Organocatalytic Modified Guareschi–Thorpe Type Regioselective Synthesis: A Unified Direct Access to 5,6,7,8-Tetrahydroquinolines and Other Alicyclic[b]‑Fused Pyridines

An unprecedented organocatalytic, regioselective, modified Guareschi–Thorpe type protocol toward the modular synthesis of 5,6,7,8-tetrahydroquinolines 22a–g and other alicyclic­[b]-fused pyridines 23–28 via the identification of Chitosan as a heterogeneous catalyst is reported. This novel strategy i...

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Bibliographic Details
Published in:Organic letters 2018-10, Vol.20 (19), p.6059-6063
Main Authors: Jaiswal, Pradeep K, Sharma, Vashundhra, Mathur, Manas, Chaudhary, Sandeep
Format: Article
Language:English
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Summary:An unprecedented organocatalytic, regioselective, modified Guareschi–Thorpe type protocol toward the modular synthesis of 5,6,7,8-tetrahydroquinolines 22a–g and other alicyclic­[b]-fused pyridines 23–28 via the identification of Chitosan as a heterogeneous catalyst is reported. This novel strategy is operationally simple and showed a wide range of functional group tolerance and substrate compatibility. The proposed mechanistic pathway involves an imine-enamine cascade approach for the synthesis of structurally diverse alicyclic­[b]-fused pyridine heterocycles. The gram scale synthesis and identification of a new class of antifungal molecules 29–31 emphasize the practicality of this method.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.8b02132