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(3 S ,4 S )‐ N ‐substituted‐3,4‐dihydroxypyrrolidines as ligands for the enantioselective Henry reaction
Author(s) -
Rénio Márcia R.R.,
Sousa Francisco J.P.M.,
Tavares Nélia C.T.,
Valente Artur J.M.,
Silva Serra M. Elisa,
Murtinho Dina
Publication year - 2021
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.6175
Subject(s) - chemistry , enantioselective synthesis , nitromethane , catalysis , chiral ligand , pyrrolidine , ligand (biochemistry) , medicinal chemistry , nitroaldol reaction , stoichiometry , substituent , coupling reaction , organic chemistry , biochemistry , receptor
The enantioselective Henry reaction is a very important and useful carbon–carbon bond forming reaction. The execution of this reaction requires the use of efficient chiral catalysts. In this work, in situ formed complexes of N ‐substituted dihydroxypyrrolidines, chiral ligands derived from L‐tartaric acid and amines, were evaluated as catalysts in the enantioselective Henry reaction. The results showed that the nature of the N ‐substituent on the ligand significantly influences the outcome of the reaction. Best results were obtained using a Cu (II) complex of (3 S ,4 S )‐ N ‐benzyl‐3,4‐dihydroxypyrrolidine, in the presence of DIPEA, for the reaction of aromatic aldehydes with nitromethane, at room temperature, originating products with er up to 92:8 ( R : S ) and conversions up to 96%. The interaction between the pyrrolidine ligand and the copper ion, in isopropanol, was followed by UV‐vis spectrophotometry, showing a 1:1 stoichiometry and a binding constant of 4.4. The results obtained will contribute to the design and development of more efficient chiral catalysts for this type of reaction.