Novel polymer-supported reagents for asymmetric catalysis
thesisposted on 19.07.2018, 09:20 by Suzanne J. Maddocks
We have developed polymer-supported β-aminoalcohol ligands for use in the asymmetric addition of diethylzinc to benzaldehyde. Linear serine- and threonine-derived polymer-supported ligands have been synthesized and tested, and several serine-derived aziridine ligands have been synthesized and tested. Polymer-supported analogues of these aziridine ligands have also been developed (scheme i). [Illustration omitted.] During the use of these aziridine ligands in the addition of diethylzinc to benzaldehyde, substrate-dependent positive nonlinear effects were observed. The effect of product inhibition to decrease the enantioselectivity induced in the reaction has also been studied, and the elimination of the product inhibition effect by the use of polymer supports has been investigated. The linear serine and threonine-derived polymer supported ligands have also been developed as epoxidation catalysts, and have been shown to catalyse the epoxidation of 1-phenyl cyclohexene with oxone. In addition the aziridine-based ligands have been shown to catalyse the asymmetric conjugate addition of diethylzinc to chalcone.
EPSRC. Charnwood Catalysis Ltd.