Synthesis of Densely Substituted Sulfonylfurans and Dihydrofurans via Cascade Reactions of α-Functionalized Nitroalkenes with β-Ketosulfones

J Org Chem. 2020 Jul 17;85(14):8825-8843. doi: 10.1021/acs.joc.0c00606. Epub 2020 Jun 25.

Abstract

The reaction of β-ketosulfones with different α-functionalized nitroalkenes affords diversely substituted sulfonylfurans and dihydrofurans. Furthermore, β-ketosulfones react with α-bromonitroalkenes and α-hydrazinonitroalkenes via a cascade Michael addition-cyclization protocol to afford nitrodihydrofurans and hydrazinodihydrofurans, respectively, bearing a key sulfonyl group, in excellent yields with a broad substrate scope. Application of these products has been demonstrated by the synthesis of pyrroles and pyrazoles in good yields. The reaction of β-ketosulfones with nitroallylic acetates yields tetrasubstituted sulfonyl furans through a cascade SN2'-intramolecular Michael reaction, followed by aromatization. The gram-scale synthesis of a representative example of sulfonylfurans was carried out to demonstrate the synthetic efficiency of the methodology.

Publication types

  • Research Support, Non-U.S. Gov't