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Enantioselective Conjugate Addition of Malononitrile to Chalcones Promoted by α,α‐ L ‐Diaryl Prolinols: Noncovalent versus Covalent Catalysis?
Author(s) -
Russo Alessio,
Capobianco Amedeo,
Perfetto Alessandra,
Lattanzi Alessandra,
Peluso Andrea
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001466
Subject(s) - chemistry , enantioselective synthesis , organocatalysis , conjugate , malononitrile , non covalent interactions , bifunctional , combinatorial chemistry , catalysis , amine gas treating , covalent bond , stereochemistry , organic chemistry , molecule , mathematical analysis , hydrogen bond , mathematics
The enantioselective conjugate addition of malononitrile to trans ‐chalcones has been investigated as a case study using easily available α,α‐ L ‐diaryl prolinols as promoters. Both experimental and computational results are consistent with a bifunctional noncovalent mode of activation of the reactive partners, provided by the secondary amine and hydroxyl groups of the promoter as general base and acid catalysis. This most energetically affordable pathway predicts predominant formation of the R ‐configured adducts, which is in agreement with the experimental findings. The present study addresses, for the first time, the ability of proline derivatives to assist product formation through noncovalent catalysis, in analogy to the mode of action typically recognized for Cinchona alkaloids.