Heterocycles via SiCl4-Promoted Isocyanide Additions to Oxonitriles

J Org Chem. 2023 Nov 17;88(22):15947-15955. doi: 10.1021/acs.joc.3c02210. Epub 2023 Nov 8.

Abstract

SiCl4 promotes isocyanide additions to oxoalkenenitriles to selectively generate 3-acylpyrroles, 2-aminofurans, or pyrrolidinones. Cyclic oxoalkenenitriles add 2 equiv of an isocyanide that installs the two core atoms of an acylpyrrole and a nitrile substituent, whereas acyclic oxoalkenenitriles add 1 equiv of an isocyanide to afford 2-aminofurans; subsequent air oxidation generates pyrrolidinones via a furan oxygenation-cleavage-cyclization sequence. The syntheses proceed under mild conditions to rapidly access three richly decorated heterocycles.