A MECHANISTICALLY DESIGNED BIS-CINCHONA ALKALOID LIGAND ALLOWS POSITION-SELECTIVE AND ENANTIOSELECTIVE DIHYDROXYLATION OF FARNESOL AND OTHER OLIGOPRENYL DERIVATIVES AT THE TERMINAL ISOPROPYLIDENE UNIT

The mechanistically designed bis-cinchona alkaloid derivative 3 serves as an excellent catalytic ligand in the OsO4-promoted catalytic enant ioselective dihydroxylation of the terminal isopropylidene group in fa rnesyl, geranylgeranyl, and solanesyl esters and also squalene, with s electivity as high as 120:1 with E,E-farnesyl acetate. H-1 NMR and X-r ay studies support the conformation described by 3 in which the U-shap ed catalytic binding pocket is composed of the two 6-(4-heptyloxy)-qui noline units (sides and rear) and the naphthopyridazine linker (bottom ).