A simple and effective soluble polymer-bound ligand for the asymmetric dihydroxylation of olefins: DHQD-PHAL-OPEG-OMe

The synthesis of a novel soluble polymer-bound ligand DHQD-PHAL-OPEG-OMe and its application in the catalytic asymmetric dihydroxylation (AD) reaction are described. 1,4-Dichlorophthalazine was used as the coupling reagent to connect dihydroquinidine and polyethylene glycol monomethyl ether (MW=5000, Fluka) while providing an aromatic group at the 9-O-position of dihydroquinidine. Enantiomeric excesses for trans-disubstituted olefins in the AD reaction, with K3Fe(CN)6 as secondary oxidant, are up to 98%.