Organic Solvent-Free, Pd(II)-Salan Complex-Catalyzed Synthesis of Biaryls via Suzuki–Miyaura Cross-Coupling in Water and Air

With
use of a Pd­(II)-sulfosalan complex as a water-soluble catalyst,
we have developed an efficient synthesis of biaryls via Suzuki–Miyaura
cross-coupling in water under aerobic conditions. The water-insoluble
target molecules were isolated by simple filtration in analytical
purity after washing with 0.01 M aqueous HCl (20 examples). In most
cases, palladium contamination was below 5 ppm considered acceptable
for active pharmaceutical ingredients. The established method is scalable,
reproducible, and provides biaryl products in isolated yields up to
91%.