Cobalt()-catalyzed hydroarylation of 1,3-diynes and internal alkynes with picolinamides promoted by alcohol

The Co( ii )-catalyzed selective C-H alkenylation of picolinamides with 1,3-diynes has been developed. This protocol can be applied to a variety of 1,3-diynes. In addition, both symmetrical and unsymmetrical internal alkynes were well tolerated, affording the corresponding alkenyl arenes. Moreover, control experiments indicated that C-H bond cleavage may be involved in the rate-determining step. Furthermore, a deuterium incorporation product was achieved when deuterated alcohol was employed as the solvent, which suggested that alcohol was essential for the final protonolysis. The Co( ii )-catalyzed selective C-H alkenylation of picolinamides with 1,3-diynes and internal alkynes for the synthesis of conjugated enynes and alkenyl arenes has been developed. The results of control experiments showed that alcohol was essential for the final protonolysis.