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Organocatalytic Modified Guareschi–Thorpe Type Regioselective Synthesis: A Unified Direct Access to 5,6,7,8-Tetrahydroquinolines and Other Alicyclic[b]‑Fused Pyridines
journal contribution
posted on 2018-09-14, 12:50 authored by Pradeep
K. Jaiswal, Vashundhra Sharma, Manas Mathur, Sandeep ChaudharyAn 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.