Direct alkenylation through C-H/C-O cleavage was accomplished under mild reaction conditions by cobalt catalysts derived from novel triazolylidene ligands. The most effective ligand is characterized by sterically demanding substituents on the 1,4-N-atoms of the triazolylidene neighboring the carbene center. The C-H alkenylations proved viable with alkenyl acetates, carbamates, carbonates and phosphates. For acyclic electrophiles, diastereoconvergent C-O functionalizations were observed.