Catalyses titanocene hydrogenation

Finally, carbohydrate ligands of enantioselective catalysts have been described for a limited number of reactions. Bis-phosphites of carbohydrates have been reported as ligands of efficient catalysts in enantioselective hydrogenations [182] and hydrocyanations [183], and a bifunctional dihydroglucal-based catalyst was recently found to effect asymmetric cyanosilylations of ketones [184]. Carbohydrate-derived titanocenes have been used in the enantioselective catalysis of reactions of diethyl zinc with carbonyl compounds [113]. Oxazolinones of amino sugars have been shown to be efficient catalysts in enantioselective palladium(0)-catalyzed allylation reactions of C-nucleophiles [185]. 

Chiral Cyclopentadienyl Complexes. Since the discovery of the polymerization activity of cyclopentadienyl complexes, they also play a key role in asymmetric catalysis (Fig. 13). Titanocene complexes of chiral tricyclic monocy-clopentadienyl ligand catalyze the enantioselective hydrogenation of unfunctionalized oleflns (105). A similar reaction has been performed with related catalysts such as chiral Ziegler-Natta systems (106) and organolanthanide systems (107). 

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