Frustrated Lewis Pairs as Hydrogenation Catalysts

By: Josephine Nakhla, ChemFiles Volume 11 Article 1

Josephine Nakhla, Ph.D.
Market Segment Manager
Organometallics and Catalysis
josephine.nakhla@sial.com


The hydrogenation of organic substrates with molecular hydrogen (H2) has been used for purposes ranging from the large-scale upgrading of crude-oil, to the synthesis of fi ne chemicals used in food, agriculture, and the pharmaceutical industry. While the majority of methods rely on the use of costly precious metal catalysts, recent work from the lab of Professor Douglas W. Stephan has illustrated the use of frustrated Lewis pairs for the same purpose.1, 2 These powerful non-metallic catalysts contain both Lewis acidic (borane) and Lewis basic (phosphine) moieties that cannot be quenched internally due to steric constraints. Because of this unquenched reactivity, these organic catalysts are used to activate a variety of small molecules, including the heterolytic cleavage of H2, leading to a powerful catalyst system for the hydrogenation of imines and aziridines (Scheme 3).

Scheme 3: Frustrated Lewis pairs for the hydrogenation of imines and aziridines.(703087),(703095)

Frustrated Lewis Pairs from Aldrich:


back to top 

Materials

     

References

  1. Welch, G. C.; San Juan, R. R.; Masuda, J. D.; Stephan, D. W. Science 2006, 314, 1124.
  2. (a) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew. Chem., Int. Ed. 2007, 46, 8050. (b) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew. Chem., Int. Ed. 2007, 46, 9136.

back to top 

Related Links