Nanofiltration for Reuse of Sharpless Catalytic Systems

Nanofiltration for reuse of Sharpless catalytic systems combines reaction and separation in a single vessel, allowing successive reaction and filtration steps, to recycle the catalytic system in successive batches with isolation of the chiral product on the permeated solution. The Sharpless catalysis is a robust strategy for production of chiral 1,2-diols from olefins at high yields and enantiomer excesses, using a catalytic system based on OsO₄ or K₂OsO₂(OH)₄ salt and a chiral dimeric ligand (Bolm et al. 2000; Kolb et al. 1994). Chiral ligands used are based on a cinchona alkaloid (dihydroquinidine or dihydroquinine) with phathalazina, pyrimidine, or indoline groups. The reaction requires a co-oxidant, which can be organic or inorganic, such as N-methylmorpholine-N-oxide (NMO) or K₃Fe(CN)₆, respectively. The reaction media is conventionally an aqueous/organic (50 v/v% solvent) mixture with tert-butanol, methyl tert-butyl ether, or acetone. The feasibility of Sharpless reaction was...