Synthesis of C 2 -symmetric bisphosphines and their application in enantioselective transition metal catalysis

Abstract

C2-symmetric bisphosphine ligands (with a dioxolane backbone) have been synthesized by using corresponding chiral bromo-substituted hydrobenzoin derivatives in two steps with moderate yields. The last step for desired bisphosphines defined the electronic and steric properties of the chelating atoms by the treatment of aryl or alkyl substituted chlorophosphine compounds in the presence of a base. These synthesized ligands have been evaluated in different catalytic reactions. The first application has been the palladiumcatalyzed enantioselective allylic alkylation which is regarded as a remarkable reaction for forming enantioselective carbon-carbon bond (up to 63 % ee and 98 % chemical yield). The ruthenium-catalyzed enantioselective transfer hydrogenation reaction has been the second application for the evaluating of the catalysts (up to > 99 % conversion with no enantioselectivity). © 2018 Croatian Chemical Society. All rights reserved.