Methanesulfonamide: a Cosolvent and a General Acid Catalyst in Sharpless Asymmetric Dihydroxylations
Mikko H. Junttila and Osmo O. E. Hormi*
*Department of Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, Finland, Email: osmo.hormioulu.fi
M. H. Junttila, O. O. E. Hormi, J. Org. Chem., 2009, 74, 3038-3047.
DOI: 10.1021/jo8026998 (free Supporting Information)
In Sharpless dihydroxylations of long chain olefins, methanesulfonamide is a cosolvent that aids in the transfer of the hydroxide ions from the water phase to the organic phase. In asymmetric dihydroxylations of conjugated aromatic olefins, the weakly acidic methanesulfonamide is a general acid catalyst that protonates the intermediate osmate esters.
see article for more examples
proposed phase transfer catalysis
M. H. Junttila, O. E. O. Hormi, J. Org. Chem., 2004, 69, 4816-4820.