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.
ABSTRACT
Thermolysis of ω-iodoalkyl-ß-siloxyalkenenitriles in DMSO triggers an oxidative cyclization cascade that affords highly oxygenated hydrindanones, decalones, and undecanones. The cyclization cascade is highly unusual on three counts: the cyclization installs a contiguous array of tertiary-quaternary-tertiary centers, thermolysis equilibrates a quaternary center, and the enolsilyl ether crossed-aldol proceeds without a catalyst.
