Copolymers quinine-acrylonitrile

Quinine-acrylonitrile copolymer. Cinchona alkaloids can be copolymerized with another vinyl monomer such as acrylonitrile with AIBN as initiator. The highest yield of polymer in the case of quinine is obtained when the quinine/acrylonitrile ratio is 1 20. This method was used to obtain a polymeric form of the alkaloid in which the crucial part of the molecule for asymmetric reactions—the amino alcohol unit—is free. The polymers are stable, light yellow solids, soluble in polar aprotic solvents (DMF and DMSO), but insoluble in common organic solvents. 

It is interesting to note that the use of poly(quinine or quinidine) copolymers with acrylonitrile as a chiral catalyst in the reaction of )S-nitrostyrene with phenylmethanethiol results in an increase in the optical rotation of the sulfide products by a factor 3 to 67. 

To explore the possibility of recycling alkaloid-Os04 complexes, several polymer-bound alkaloid derivatives have been used for heterogeneous catalytic asymmetric dihydroxylations. As chiral ligands, polymerized cinchona alkaloids or copolymers of quinine derivatives with acrylonitrile or styrene were studied [46]. In general, lower select vities and decreased rates were observed. 

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