Lanthanide (III) salt complexes: Arrayed acid-base networks for enantioselective catalysis. The nitroaldol reaction upon aldehydes and trifluoromethylketones
| Autor: | José González, José M. Saá, Fernando Tur |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Pharmacology
Lanthanide Trifluoromethyl Nitroaldol reaction Organic Chemistry Enantioselective synthesis Catalysis Analytical Chemistry chemistry.chemical_compound chemistry Asymmetric carbon Drug Discovery Polymer chemistry Organic chemistry Chirality (chemistry) Trifluoromethanesulfonate Spectroscopy |
| Zdroj: | Chirality. 21:836-842 |
| ISSN: | 1520-636X 0899-0042 |
| DOI: | 10.1002/chir.20698 |
| Popis: | Shelf stable, chiral-at-metal, D3 symmetric, 3:1 complexes of lanthanide (III) triflate salts are easily available by complexation with binolam (3,3′-diethylaminomethyl-2,2′-dihydroxy-1,1′-dinaphthalene) 1 or binolamo (3,3′-diethylaminooxymethyl-2,2′-dihydroxy-1,1′-dinaphthalene) 2 ligands. The resulting compounds 3Ln and 4Ln are isostructural, as demonstrated by their spectroscopic data, and possess an arrayed acid-base LABABB network. Complexes are kinetically labile, and in solution undergo hydrolysis by water. The lanthanum complex derived from binolam, i.e., (Δ,S,S,S)- (binolam)3.la(OTf)33La was found to be the most active catalyst in promoting direct nitroaldol reactions upon aldehydes and trifluoromethyl ketones, thereby giving rise to secondary nitroalcohols and tertiary α-trifluoromethyl-β-nitroalcohols, respectively, with high ee in both cases. Enantiomerically enriched tertiary nitroalcohols were easily reduced to the corresponding aminoalcohols having a quaternary asymmetric carbon without loss of enantiomeric purity. Chirality 2009. © 2009 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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