Substrate-Controlled Divergent Synthesis of Polysubstituted 2-Imidazolone and Imidazole Derivatives via a Three-Component Tandem Reaction of Sulfur Ylide, Nitrosobenzene, and Isonitrile

A base-mediated three-component reaction has been developed to selectively synthesize polysubstituted 2-imidazolones and imidazoles from sulfur ylides, nitrosobenzene, and isonitrile under mild, catalyst-free conditions. The reaction pathway can be controlled by modifying the structure of the active isocyanide. Plausible mechanisms have been proposed to explain the observed reactivity.