Process-scale preparation of enantiomerically pure g-lactones by asymmetric hydrogenation of g-ketoesters and comparative tests of the sensory properties of some antipodes
| Autor: | Alessandro Ponti, Ella Pagliarini, Lorenzo de Ferra, Tullio Pilati, Tiziana Benincori, Mara Sada, Celentano Giuseppe, S. Ratti, Simona Rizzo, Franco Sannicolò |
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| Rok vydání: | 2004 |
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| Zdroj: | Tetrahedron: asymmetry 15 (2004): 2289–2297. doi:10.1016/j.tetasy.2004.06.024 info:cnr-pdr/source/autori:Benincori, T.; Rizzo, S.; Pilati, T.; Ponti, A.; Sada, M.; Pagliarini, E.; Ratti, S.; Celentano, G.; de Ferra, L.; Sannicolò F./titolo:Process-scale preparation of enantiomerically pure b-lactones by asymmetric hydrogenation of beta-keto esters and comparative tests of the sensory properties of some antipodes/doi:10.1016%2Fj.tetasy.2004.06.024/rivista:Tetrahedron: asymmetry (Print)/anno:2004/pagina_da:2289/pagina_a:2297/intervallo_pagine:2289–2297/volume:15 |
| DOI: | 10.1016/j.tetasy.2004.06.024 |
| Popis: | A reliable methodology, applicable on a process-scale level, for producing enantiomerically pure chiral γ-lactones by enantioselective hydrogenation of γ-ketoesters, followed by cyclisation of the resulting γ-hydroxyesters, has been developed. The multi-step procedure was transformed into a one-pot reaction. A very efficient chiral Ru-complex, based on the biheteroaromatic diphosphine ligand tetraMe-BITIOP, was developed as a catalyst, capable of coupling fast kinetics with high stereoselection levels. Its structure was fully elucidated through 31P NMR, EPR and X-ray single-crystal analyses. The optimal experimental conditions are as follows: hydrogen pressure = 30 psi, S/C ratio = 2000, 30% in weight substrate concentration. Yields are quantitative and enantiomeric excesses in the range 98–99.9%. Sensorial tests on the antipodes of two γ-lactones demonstrated the very different properties of the enantiomers. |
| Databáze: | OpenAIRE |
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