The RuO4‐Catalyzed Ketohydroxylation, Part II:A Regio‐, Chemo‐ and Stereoselectivity Study

The direct RuO4‐catalyzed ketohydroxylation of olefins is a new and convenient method for the preparation of a wide range of symmetrical and unsymmetrical α‐hydroxy ketones. Since reactions in which two different functional groups are introduced in one step always involve regio‐, chemo‐ and stereoselectivity issues, this paper gives a full account of investigations of various selectivity aspects in the ketohydroxylation. Stereoselectivity issues were examined in the final part of the present report. The Kishi rules, known from OsO4‐catalyzed dihydroxylations, are found to be valid for the RuO4‐catalyzed ketohydroxylation and lead to moderate to good diastereomeric ratios in the oxidation of olefins possessing an allylic center of chirality. Furthermore, competition experiments between different substituted olefins led to a reactivity profile applicable to the prediction of which is the most reactive of different C=C double bonds present in a molecule. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)