Cobalt-catalyzed cross-coupling between in situ prepared arylzinc halides and 2-chloropyrimidine or 2-chloropyrazine

A cobalt-catalyzed cross-coupling of aryl halides with 2-chloropyrimidines or 2-chloropyrazines is reported in satisfactory to high yields. The key step of this procedure is the formation of aromatic organozinc reagents and their coupling with 2-chlorodiazines using the same cobalt halide as catalyst and Zn dust under mild reaction conditions. This new cobalt-catalyzed coupling reaction represents a practical and interesting alternative to previously known methods for the synthesis of 2-aryldiazines.