Asymmetric Suzuki-Miyaura Coupling in Water Using a Chiral Polymeric Pd Catalyst

Significance

Asymmetric Suzuki-Miyaura coupling in water with a novel recyclable palladium complex of a polymer-supported chiral imidazo­indole phosphine ligand was described. Thus, PS-PEG-supported imidazoindole dicyclohexyl­phosphine (PS-PEG-L*, 7) was prepared from PS-PEG-NH₂ and compound 6. The reaction of 2-methyl-1-iodonaphthalene with 2-methylnaphthyl boronic acid was catalyzed by the amphiphilic polymeric PS-PEG-L*-Pd complex to give 2,2′-dimethyl-1,1′-binaphthyl in 95% yield with 94% ee (S). The catalyst PS-PEG-L*-Pd was recovered readily and reused four times with little loss of its catalytic activity and stereoselectivity.