Enantioselective Synthesis of Octahydrofuranoindole Core of Aspidosperma Alkaloids via a Diels-Alder/Reduction/Fluoroetherification Reaction Sequence

Madavi S Prasad; Ms Sankar Bharani; Mr Aman Kumar Jha; Mr Sugali Chetan Naik; Murugesan Sivaprakash; L Raju Chowhan

doi:10.1002/asia.202300419

Enantioselective Synthesis of Octahydrofuranoindole Core of Aspidosperma Alkaloids via a Diels-Alder/Reduction/Fluoroetherification Reaction Sequence

Chem Asian J. 2023 Aug 15;18(16):e202300419. doi: 10.1002/asia.202300419. Epub 2023 Jul 20.

Authors

Madavi S Prasad¹, Ms Sankar Bharani¹, Mr Aman Kumar Jha¹, Mr Sugali Chetan Naik¹, Murugesan Sivaprakash¹, L Raju Chowhan²

Affiliations

¹ Asymmetric synthesis and catalysis laboratory, Department of Chemistry, Central University of Tamil Nadu (CUTN)., Tiruvarur, 610 005, India.
² School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.

PMID: 37415449
DOI: 10.1002/asia.202300419

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).

Keywords: Aspidosperma alkaloids; Diels Alder; enantio-selective synthesis; octahydrofuranoindoles; organocatalysis.

Abstract

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