Chiral Sulfonamide Phosphine Catalyst Immobilization And Recycling

Immobilized catalyst means that catalyst is immobilized to some medium to achieve the target of homogeneous catalysis translation to heterogeneous catalysis, which is in favor of the recovery of the catalysts, handling and the cost of production. Immobilization chiral catalysts meet the demands of green chemistry. This paper launched phosphine ligands and their complexes, which contains two parts.Recently, gold catalyst is one of the hot topics. Gold catalyst has some advantages of mild reaction condition, functional good compatibility and selectivity, because one valence and tervalence gold has unique carbophilic π-Lewis acid. Due to expensive gold and chiral ligand, homogeneous catalyst was immobilized to some materials, this method not only can reused chiral metal complex, but also reduced the residual quantity of metal. Our group had developed a series of chiral sulfonamide phosphine ligands. Gold catalysts showed good performance in asymmetric [3+3] cycloaddition. The polymer-bound Ming-phos polystyrene was easily prepared by copolymerization with styrene. The degree of cross-linking of polystyrene was investigated. Enantioselectivity of reaction was optimal in the present of 5 mol% DVB. A pair of enantiomers of the product could be easily delivered in high yields with excellent enantioselectivity by the application of two enantiomers of the heterogeneous catalyst. They not only exhibited similar catalytic activity and enantioselectivity to homogeneous catalyst, but also be easily recovered and recycled for up to 8 cycles. Unfortunately, the activity of catalyst had some reduction.Phosphine-catalyzed is a hot topic in organocatalysis. Due to phosphine have strong nucleophilicity and some advantages of mild reaction condition, selectivity, no metal pollution. We did some researches that the mechanism of reaction catalyzed by Xiao-phos phosphine. We tried to immobilize the phosphine catalyst, phenolic hydroxyl was introduced into para-position of the phosphine catalyst, then phenolic hydroxyl had selectively reacted with 1-(bromomethyl)-4-vinylbenzene, this method had achieved the functional group of ligand. The phosphine catalyst contained styryl group reacted with styrene by copolymerization, and afforded polymer-catalyst. The catalyst had not only achieved the target of excellent enantioselectivity and good yield, but also the ability of recovery.