Heck Reaction of ArylN₂BF₄ with Acrylates Catalyzed by Pd

Significance

The Pd/C-catalyzed Heck coupling of aryldiazonium tetrafluoroborates is reported. Thus, the Heck coupling of aryldiazonium tetra­fluoroborates 1 with acrylates or an acrylamide 2 was carried out with Pd(II)/C_eggshell [= Pd(II)/C where Pd(II) is distributed close to the surface of the charcoal] to give the corresponding cinnam­ates 3a-l in 43-98% yield (12 examples). The reused catalyst suffered from a significant deactivation, affording 3g in 82 (1^st use), 41 (2^nd use) and 32% yield (3^rd use). The aggregation of Pd nanoparticles (Æ 20 nm@fresh catalyst vs. Æ 60 nm@used catalyst) should result in deactivation of the catalyst.