Rh(II)-Catalyzed [2,3]-Sigmatropic Rearrangement of Sulfur Ylides Derived from Cyclopropenes and Sulfides

A new type of Rh₂(OAc)₄-catalyzed [2,3]-sigmatropic rearrangement of sulfur ylides is reported. A series of cyclopropenes were successfully employed for [2,3]-sigmatropic rearrangement by a reaction with either allylic or propargylic sulfides. Under the optimized conditions, the reaction afforded the products in moderate to excellent yields. In these transformations, the vinyl metal carbenes generated in situ from the cyclopropenes were effectively trapped by sulfides, resulting in the formation of corresponding products upon [2,3]-sigmatropic rearrangements

Ru(II)-Catalyzed Cross-Coupling of Cyclopropenes with Diazo Compounds: Formation of Olefins from Two Different Carbene Precursors

Formal carbene dimerization is a convergent method for the synthesis of alkenes. Herein, we report a Ru­(II)-catalyzed carbene dimerization of cyclopropenes and diazo compounds. The yields are up to 97% and the stereoselectivity are up to >20:1. Mechanistically, it has been experimentally demonstrated that the catalyst reacts with cyclopropene first to generate a Ru­(II)–carbene species, which is attacked by nucleophilic diazo substrate, followed by dinitrogen extrusion to form the double bond