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Asymmetric Anion-π Catalysis on Perylenediimides
Chao Wang1, François N Miros1, Jiri Mareda1
1Department of Organic Chemistry, University of Geneva, Geneva, Switzerland.
Angewandte Chemie (International Ed. in English)
|October 15, 2016
Summary
Perylenediimides (PDIs) now advance anion-π catalysis, surpassing naphthalenediimides (NDIs). PDI catalysts achieve record quadrupole moments and high enantioselectivity by optimizing π-surface twist for superior electrostatic interactions.
Area of Science:
- Organic Chemistry
- Catalysis
- Supramolecular Chemistry
Background:
- Anion-π catalysis utilizes π-acidic aromatic surfaces to stabilize anionic transition states.
- Naphthalenediimides (NDIs) have been the primary scaffolds for developing anion-π catalysis.
Purpose of the Study:
- To introduce perylenediimides (PDIs) as novel scaffolds for anion-π catalysis.
- To investigate the structure-activity relationships of PDI catalysts in promoting chemical transformations.
- To explore the role of electrostatic interactions versus redox properties in PDI-mediated anion-π catalysis.
Main Methods:
- Synthesis and characterization of perylenediimide (PDI) catalysts.
- Evaluation of PDI catalytic activity in enolate and enamine addition reactions.
- Nitrate inhibition studies and circular dichroism (CD) spectroscopy to probe catalytic mechanisms.
Main Results:
- PDIs exhibit significantly higher quadrupole moments than NDIs, reaching up to +70.9 B.
- Catalytic activity of PDIs is governed by the twist of their π surface, not reducibility.
- Highest enantioselectivities (96% ee) in anion-π catalysis were achieved using PDI catalysts.
- Nitrate inhibition and CD spectroscopy support electrostatic interactions (quadrupole moments) as the key driving force.
Conclusions:
- Perylenediimides represent a new class of highly effective catalysts for anion-π catalysis.
- The quadrupole moment is a critical parameter for designing efficient anion-π catalysts.
- PDI catalysts enable unprecedented levels of enantioselectivity in anion-π transformations.
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