Continuous Asymmetric Synthesis in a Membrane Reactor

Adapted from biocatalytic reactions the principle of the membrane reactor (represented schematically on the right) is applicable to the continuous asymmetric addition of diethylzinc to benzaldehyde. α,α-Diphenyl-L-prolinol is coupled to a homogeneously soluble polymer (1), which enables it to be retained in the reaction vessel by an ultrafiltration membrane. By decoupling the residence time of reactants and the catalyst the total turnover number could be increased by a factor of 10.