The cobalt-catalyzed cross-coupling of organozinc bromides is described. In the case of arylzinc reagents, the same cobalt catalyst, CoBr 2

Cobalt-Catalyzed Cross-Coupling of Organozinc Halides with Bromoalkynes.-Highly substituted phenylacetylene derivatives are synthesized by using title method. The reaction tolerates various functional groups, such as ester, nitrile, halide, pyridine, boronic ester, etc. In the case of arylzinc reagents, both CoBr 2(phen) and CoBr2 catalyze the formation of organozinc halides and the cross-coupling reaction, but the former gives higher yields for the reaction with alkyl-substituted bromoalkynes and for the reaction with arylzinc halides bearing electron-withdrawing groups [e.g. in the synthesis of (VIa)]. In the case of synthesizing dialkylalkynes, the method used for the preparation of the organozinc halides significantly influences the outcome of the cross--coupling reaction. Chloroalkyne is also used in the case of synthesizing (VIIIa) and gives similar yield. -(CORPET, M.; BAI, X.-Z.; GOSMINI*, C.; Adv. Synth. Catal. 356 (2014) 14-15, 2937-2942, http://dx.doi.org/10.1002/adsc.201400369 ; Lab. Heteroelem. Coord., CNRS, Ec. Polytech., F-91128 Palaiseau, Fr.; Eng.) -L. Grundl 11-077