(Salen)ruthenium-catalyzed desymmetrization of meso-diols (2).: Apical ligand effect on enantioselectivity

Enantiotopos-selectivity of aerobic oxidation of meso-diols using chiral (nitrosyl)Ru(salen) complexes as catalyst was found to be dependent on the nature of their apical ligand. The oxidation with complex 5 possessing an apical hydroxo ligand as the catalyst showed moderate to good enantioselectivity (up to 80% ee).