Ruthenium(II)-catalyzed cross-dehydrogenative C–H alkenylations by triazole assistance

Abstract Ruthenium(II) carboxylate complexes allowed for efficient cross-dehydrogenative alkenylations of N -aryl-1,2,3-triazoles. The twofold C–H functionalizations occurred with excellent chemo-, regio-, site- and diastereoselectivities, and ample substrate scope. The versatile ruthenium(II) catalyst proved tolerant of moisture, air, and various electrophilic functional groups. Mechanistic studies were in good agreement with an initial C–H metalation by a cationic ruthenium(II) carboxylate, along with a subsequent migratory insertion of the olefin.