KINETIC CONSTRAINTS ON POSSIBLE REACTION, PATHWAYS FOR OSMIUM-CATALYZED ASYMMETRIC DIHYDROXYLATION

Proposed mechanisms for the osmium-catalysed dihydroxylation are exami ned and kinetic rate laws derived in terms of various mechanistic rate constants. In light of the reported kinetic behaviour of these system s, particularly with asymmetric nitrogen base ligands, several constra ints can be placed on the two major competing hypotheses. The chemical consequences of these constraints make stepwise formation of the two C-O bonds via an osmaoxetane the more plausible mechanistic model.