| SYNTHESIS |
Authors discovered that the reaction rate and enantioselectivity could be maximized by carefully controlling the relative concentrations of platinum and cinchonidine. Even though the group ran the reaction at less than one-tenth of the hydrogen pressure typically used, they achieved an enantiomeric excess of 94% by maintaining a ratio of roughly 10 atoms per modifier molecule. THE PROBLEM, however, is that it's tough to hold the Pt-to-modifier ratio at the optimum level because cinchonidine is destroyed by the acetic acid solution in which the reaction is carried out. So rather than dumping a large excess of the modifier into the pot at the start of the reaction (and starting out at the wrong ratio), so authors developed a procedure for adding the organic substance slowly and precisely during the course of the reaction--thereby maintaining optimum reaction conditions and high enantioselectivity
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