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%.