Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The hyroxylation of α,β-unsaturated esters catalyzed by osmium-tetroxide leads to 3,4-dihydroxy-lactones of predictable stereochemistry. ... J. Org. Chem., 48 (1983), p. 1217 It is not entirely clear, however, that these cases do not simply reflect steric factors.