On the Stereoselectivity in Bisdihydroxylation of 1,5-Cyclooctadiene with Osmium Tetroxide.

In the bisdihydroxylation of 1,5-cyclooctadiene with OsO4, use of a stoichiometric amount of OsO4 yielded a 1:1 mixture of syn- and anti-isomers, while use of a catalytic amount of OsO4 gave only syn- (1R *,2S *,5R *,6S *)-cyclooctane-1,2,5,6- tetrol. This syn-selectivity was attributed to the favorable formation of an intramolecular osmium(VI) bisglycolate ester in the catalytic reaction.