Enantioselective Synthesis of Octahydrofuranoindole Core of Aspidosperma Alkaloids via a
Madavi S Prasad1, Ms Sankar Bharani1, Mr Aman Kumar Jha1
1Asymmetric synthesis and catalysis laboratory, Department of Chemistry, Central University of Tamil Nadu (CUTN)., Tiruvarur, 610 005, India.
Abstract:
Herein, we disclose the enantioselective synthesis of novel tricyclic fluorooctahydrofuranoindole spirooxindoles bearing five contiguous stereocenters via an organocatalytic sequential Diels-Alder/Reduction/Fluoroetherifiction reaction strategy. The potential of the developed approach was witnessed by generating vast examples (up to 20 examples) of library molecules embedding natural product core with good yields and phenomenal diastereo- and enantioselectivities (up to 77 % overall yield, up to 99 % ee and 10 : 1 dr). The synthetic utility of our protocol was further demonstrated by synthesizing tricyclic iodooctahydroindole spirooxindole framework through sequential Diels-Alder/reduction/iodoetherification reaction in 65 % overall yield and excellent stereoselectivity (99 % ee and 4 : 1 dr).
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