ORGANIC
LETTERS
2003
Vol. 5, No. 18
3353-3356
An Improved Protocol for the
RuO -Catalyzed Dihydroxylation of
4
Olefins
Bernd Plietker* and Meike Niggemann
Organische Chemie II, Fachbereich Chemie, UniVersita¨t Dortmund, Otto-Hahn-Str. 6,
D-44221 Dortmund, Germany
Received July 18, 2003
ABSTRACT
Dihydroxylation under ruthenium catalysis provides an easy access to syn-diols, although overoxidation is a common side reaction. Furthermore,
the high catalyst loadings offset the lower price of ruthenium compared to osmium. In this paper, we present an improved protocol for the
RuO -catalyzed syn-dihydroxylation using only 0.5 mol % catalyst under acidic conditions. A variety of olefins can be hydroxylated in good
4
to excellent yields with only minor formation of side products.
Transition-metal-catalyzed oxidations of C,C-double bonds
have been a major topic in chemical research for more than
30 years.1 As a result, they have become one of the most
commonly used transformations in organic synthesis. Among
these reactions, the osmium-catalyzed dihydroxylation in its
asymmetric version represents a benchmark when it comes
to generality and selectivity.2 Despite its success, some
problems still need to be solved. The oxidation is limited to
electron-rich or mono-, di-, and in some cases, trisubstituted
olefins.3 Furthermore, the osmium catalyst is toxic and very
expensive. Alternative oxidants have been described for this
reaction; however, RuO4, as a dihydroxylation catalyst, is
most promising.4 In 1954, Djerassi introduced RuO4 in
organic chemistry.5 Since then, it has mainly been used for
the degradation of unsaturated organic compounds.6 How-
ever, in ethyl acetate/acetonitrile/water a very fast dihy-
droxylation of olefins using 7 mol % of RuO4 was observed.4
Longer reaction times resulted in the formation of fission
products.
During the course of our studies on the stability of
ruthenate esters, we became interested in the RuO4-catalyzed
dihydroxylation reaction. The hydrolysis of these cyclic esters
plays a key role in our attempts to develop new oxidation
reactions. Based on literature results and our own investiga-
tions, we envisioned the intermediate ruthenates to be
responsible for the oxidative fragmentation. Three different
scenarios could lead to the formation of fission products.
First, an electrocyclic C,C-bond cleavage in either III or V
(1) Houben-Weyl. StereoselectiVe Synthesis; Helmchen, G., Hoffmann,
R. W., Mulzer, J., Schaumann, E., Eds.; Thieme-Verlag: Stuttgart, New
York, 1996; Vol. 8, Chapter 4, p 4497.
(4) (a) Shing, T. K. M.; Tai, V. W.-F.; Tam, E. K. W. Angew. Chem.
1994, 106, 2408; Angew. Chem., Int. Ed. Engl. 1994, 33, 2312. (b) Shing,
T. K. M.; Tam, E. K. W.; Tai, V. W. F.; Chung, I. H. F.; Jiang, Q. Chem.
Eur. J. 1996, 2, 50.
(5) Djerassi, C.; Engle, R. R. J. Am. Chem. Soc. 1953, 75, 3839.
(6) (a) Martin, V. S.; Palazon, J. M.; Rodriguez, C. M. In Oxidizing and
Reducing AgentssHandbook of Reagents for Organic Synthesis; Burke, S.
D., Danheiser, R. L., Eds.; Wiley-VCH: Weinheim, New York, 1999; p
346. (b) Courtney, J. L. In Organic Syntheses by Oxidation with Metal
Compounds; Mijs, W. J., de Jonge, C. R. H. I., Eds.; Plenum Press: New
York, London, 1986; p 445.
(2) (a) Johnson, R. A.; Sharpless, K. B. In Catalytic Asymmetric Synthesis,
2nd ed.; Ojima, I., Ed.; Wiley-VCH: New York, Weinheim, 2000; p 357.
(b) Bolm, C.; Hildebrand, J. P.; Muniz, K. In Catalytic Asymmetric Synthesis,
2nd ed.; Ojima, I., Ed.; Wiley-VCH: New York, Weinheim, 2000; p 399.
(3) (a) Becker, H.; Sharpless, K. B. In Asymmetric Oxidation Reactions;
Katsuki, T., Ed.; Oxford University Press: New York, 2001; p 81. (b)
Morikawa, K.; Park, J.; Andersson, P. G.; Hashiyama, T.; Sharpless, K. B.
J. Am. Chem. Soc. 1993, 115, 8463.
10.1021/ol035335a CCC: $25.00 © 2003 American Chemical Society
Published on Web 08/14/2003