Asymmetric counteranion-directed catalysis

Asymmetric counteranion-directed catalysis (ACDC) [1] or chiral anion catalysis [2] in enantioselective synthesis is ""induction of enantioselectivity in a reaction proceeding through a cationic intermediate by means of ion pairing with a chiral, enantiomerically pure anion provided by the catalyst".[1] The ACDC concept was introduced in 2006 by Benjamin List,[3]

In 2000 Llewellyn, Adamson & Arndtsen used a chiral borate anion in olefin aziridination and cyclopropanation.[4] Chiral anions were also described by Dean Toste in 2007 [5] and by Rueping also in 2007.[6] Ion pairing is loosely defined and ACDC includes enantioselective Brønsted acid catalysis. ACDC is deployed in area's of scientific research such as organocatalysis, transition-metal catalysis and Lewis acid catalysis.

Examples of enantioselective catalysis include allene hydroxyalkoxylation (Toste 2007) in which the active catalyst is a salt of gold(I) and a phosphate of a chiral binaphthol:[7][8]

A similar system (Reuping, 2007) was used in an alkynylation of an imino ester.

References

  1. 1 2 Mahlau, M.; List, B. (2013). "Asymmetric Counteranion-Directed Catalysis: Concept, Definition, and Applications.". Angew. Chem. Int. Ed. 52: 518–533. doi:10.1002/anie.201205343.
  2. ↑ Phipps, Robert J.; Hamilton, Gregory L.; Toste, F. Dean (2012). "The progression of chiral anions from concepts to applications in asymmetric catalysis". Nature Chemistry 4: 603–614. doi:10.1038/nchem.1405.
  3. ↑ Mayer, S.; List, B. (2006). "Asymmetric Counteranion-Directed Catalysis". Angew. Chem. Int. Ed. 45: 4193–4195. doi:10.1002/anie.200600512.
  4. ↑ Llewellyn, David B.; Adamson, Dan; Arndtsen, Bruce A. (2000). "A Novel Example of Chiral Counteranion Induced Enantioselective Metal Catalysis:? The Importance of Ion-Pairing in Copper-Catalyzed Olefin Aziridination and Cyclopropanation". Organic Letters 2 (26): 4165–4168. doi:10.1021/ol000303y.
  5. ↑ Hamilton, Gregory L.; Joo Kang, Eun; Mba, Miriam; Toste, F. Dean (2007). "A Powerful Chiral Counterion Strategy for Asymmetric Transition Metal Catalysis". Science 317 (5837): 496–499. doi:10.1126/science.1145229.
  6. ↑ Rueping, M.; Antonchick; Brinkmann, C. (2007). "Dual Catalysis: A Combined Enantioselective Brønsted Acid and Metal-Catalyzed Reaction—Metal Catalysis with Chiral Counterions". Angew. Chem. Int. Ed. 46: 6903–6906. doi:10.1002/anie.200702439.
  7. ↑ A Powerful Chiral Counterion Strategy for Asymmetric Transition Metal Catalysis Gregory L. Hamilton, Eun Joo Kang, Miriam Mba, F. Dean Toste. Science 317, 496 (2007) doi: 10.1126/science.1145229
  8. ↑ Starting catalyst: 1,2-bis(diphenylphosphino)ethane (dppm) gold(I) chloride complex
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