Asymmetric Organocatalysis Sarah maifeld September 19, 2002
Asymmetric Organocatalysis Sarah Maifeld September 19, 2002
Approaches to Asymmetric Catalysis Organometallic catalysis Broad scope Ligand control Inert conditions Cost and toxicity Bioorganic catalysis Highly selective High rate of reaction Limited scope
Approaches to Asymmetric Catalysis • Organometallic catalysis – Broad scope – Ligand control – Inert conditions – Cost and toxicity • Bioorganic catalysis – Highly selective – High rate of reaction – Limited scope
Organocatalysis Similar modes of action Lewis acidic/Lewis basic functionality Enzyme mimetics Advantages Preparative expensive Amenable to combinatorial approaches
Organocatalysis • Similar modes of action – Lewis acidic/Lewis basic functionality – Enzyme mimetics • Advantages – Preparative – Inexpensive – Amenable to combinatorial approaches
History and Development Early example OH catalytic Hcn quInine CN Applications 10%ee -Kinetic resolutions -Phase transfer catalysis -Asymmetric synthesis Bredig, G; Fiske, P S. Biochem. Z. 1912, 46,7 Prelog, V. Wilhelm, M. He/v. Chim. Acta 1954, 37, 1634
History and Development • Early example Bredig, G.; Fiske, P. S. Biochem. Z. 1912, 46, 7. Prelog, V.; Wilhelm, M. Helv. Chim. Acta 1954, 37, 1634. H O HCN CN OH + 10% ee catalytic quinine •Applications –Kinetic resolutions –Phase transfer catalysis –Asymmetric synthesis
Outline Cinchona alkaloids Proline Amino acid derivatives Peptide-like Catalysts Heteroazolium species
Outline • • Cinchona Alkaloids • Proline • Amino Acid Derivatives • Peptide-like Catalysts • Heteroazolium Species