The research involves electrochemically promoted catalytic asymmetric hydrogenation using chiral palladium complexes (L-L)PdCl2, where L-L is a chiral, bidentate, iminium ligand. Electrochemical reduction of the Pd(II) with loss of chloride ion gives a coordinatively unsaturated (L-L)Pd complex, which is part of a catalytic cycle involving coordination of an unsaturated prochiral substrate E=CR'R",and reduction with 2e- and 2H+ to give HEC*HR'R", regenerating (L-L)Pd. The product may be an alkane or amine, depending on whether E is CH2 or NH, and will be analyzed by GC/MS, chiral GC and/or LC, and NMR with chiral shift reagents. Once effective homogeneous catalysts and reaction conditions have been found, heterogeneous hydrogenations, with the catalyst tethered to the electrode, will be explored.
With this POWRE award the Chemistry Division supports the work of Dr. Bernadette T. Donovan-Merkert in the Department of Chemistry at the University of North Carolina at Charlotte. The research is directed toward electrochemistry as a means to carry out selective asymmetric synthesis, based on the electrochemical reduction of olefins and imines in the presence of palladium complexes with chiral ligands. Reactions of this type have the potential of producing useful pharmaceuticals and agrochemicals under mild conditions and with high selectivities for the desired product in an environmentally benign fashion.
