Biocatalyst metal-catalyzed hydrogenation

The award of the Nobel Prize in Chemistry in 2001 to William R. Knowles and Ryoji Noyori for their work on metal-catalyzed enantioselective hydrogenation reactions and to K. Barry Sharpless for his work on catalyzed enantioselective oxidation reactions was a landmark in chiral catalysis studies. Enzymes and biocatalysts have also played a pivotal role as asymmetric catalysts [16]. 

Transition metal catalysts and biocatalysts can be combined in tandem in very effective ways as shown by the following example (Scheme 2.21). An immobilized rhodium complex-catalyzed hydrogenahon of 46 was followed by enzymatic hydrolysis of the amide and ester groups of 47 to afford alanine (S)-9 in high conversion and enanhomeric excess. Removal of the hydrogenation catalyst by filtration prior to addition of enzyme led to improved yields when porcine kidney acylase 1 was used, although the acylase from Aspergillus melleus was unaffected by residual catalyst [23]. 

---