Highly enantioselective catalytic asymmetric ring opening reaction employing the Daniphos ligand

A set of the recently published planar-chiral Daniphos diphosphine ligands, based on an arene chromium tricarbonyl scaffold, has been applied to the rhodium-catalyzed asymmetric ring opening (ARO) reaction of 1,4-dihydro-1,4-epoxynaphthalene with methanol as the nucleophile. Enantioselectivities of up to 97.5% ee at satisfactory conversions have been obtained. The most successful ligand showed to be a PPh2/P(t-Bu)2-substituted derivative. An X-ray structure of this ligand is presented and discussed.