112607-22-4Relevant academic research and scientific papers
Process-scale preparation of enantiomerically pure γ-lactones by asymmetric hydrogenation of γ-ketoesters and comparative tests of the sensory properties of some antipodes
Benincori, Tiziana,Rizzo, Simona,Pilati, Tullio,Ponti, Alessandro,Sada, Mara,Pagliarini, Ella,Ratti, Simona,Giuseppe, Celentano,De Ferra, Lorenzo,Sannicolo, Franco
, p. 2289 - 2297 (2004)
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=30psi, 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.
Palladium/Zinc Co-Catalyzed Asymmetric Hydrogenation of γ-Keto Carboxylic Acids
Zhang, Keyang,Zhang, Xuexin,Chen, Jingchao,Liu, Zixiu,Pan, Chunxiang,Zhu, Yuanbin,Wu, Shiyuan,Fan, Baomin
supporting information, p. 1229 - 1232 (2021/05/03)
A palladium-catalyzed asymmetric hydrogenation of levulinic acid has been successful developed by using Zn(OTf)2 as co-catalyst. The present method not only has provided a strategy in the palladium-catalyzed asymmetric hydrogenation of ketone, but also allowed the preparation of a wide range of chiral γ-valerolactones in good yields with excellent enantioselectivities.
Carboxyl Group-Directed Iridium-Catalyzed Enantioselective Hydrogenation of Aliphatic ?-Ketoacids
Li, Mao-Lin,Li, Yao,Li, Yi-Hao,Pan, Jia-Bin,Song, Song,Zhou, Qi-Lin,Zhu, Shou-Fei
, p. 10032 - 10039 (2020/10/18)
Although the transition metal-catalyzed asymmetric hydrogenation of aromatic ketones has been extensively explored, the enantioselective hydrogenation of aliphatic ketones remains a challenge because chiral catalysts cannot readily discriminate between the re and si faces of these ketones. Herein, we report a carboxyl-directing strategy for the asymmetric hydrogenation of aliphatic ?-ketoacids. With catalysis by iridium complexes bearing chiral spiro phosphino-oxazoline ligands, hydrogenation of aliphatic ?-ketoacids afforded chiral ?-hydroxylacids with high enantioselectivity (up to 99% ee). Mechanistic studies revealed that the carboxyl group of the substrate directs hydrogen transfer and ensures high enantioselectivity. Density functional theory calculations suggested the occurrence of chiral induction involving a hydrogen-hydrogen interaction between a hydride on the iridium atom and the substituent on the oxazoline ring of the ligand, and on the basis of the calculations, we proposed a catalytic cycle involving only Ir(III), which differs from the Ir(III)/Ir(V) catalytic cycle that operates in the hydrogenation of α,β-unsaturated carboxylic acids.
Preparation of optically active 4-substituted γ-lactones by lipase-catalyzed optical resolution
Shimotori, Yasutaka,Hoshi, Masayuki,Inoue, Keita,Osanai, Takeshi,Okabe, Hayato,Miyakoshi, Tetsuo
, p. 165 - 174 (2015/06/25)
Optically active 4-substituted γ-lactones (3 and 4) were synthesized effectively using lipase-catalyzed optical resolution. N-methyl-4-hydroxyalkanamides (rac-1a-i) as substrates were prepared from N-methylsuccinimide. The alkylation of N-methylsuccinimid
Catalytic enantioselective synthesis of 2-alkylcyclobutanones and 4-alkyl-γ-butyrolactones from alkylidenecyclopropanes and the Sharpless AD-mix reagent
Krief, Alain,Ronvaux, Alain,Tuch, Arounarith
, p. 699 - 702 (2007/10/03)
Reaction of AD-mix with alkylidenecyclopropanes allows the synthesis of optically active 2-alkylcyclobutanones and 4-alkyl-γ-butyrolactones after stepwise pinacolic rearrangement and Beyer-Villiger oxidation.
Baker's yeast reduction of arylalkyl and arylalkenil γ- and δ-keto acids
Aquino, Mario,Cardani, Silvia,Fronza, Giovanni,Fuganti, Claudio,Fernandez, Rosalino Pulido,Tagliani, Auro
, p. 7887 - 7896 (2007/10/02)
γ- and δ-Lactones 5, 6, 13, 14, 15 and 16 were synthesized via baker's yeast reduction of the corresponding keto acids 3, 4 and 9-12. The enantioselectivity of the reduction is strongly dependent on the nature of the keto acid; the δ-lactones ware always obtained in an ee% higher than the γ-lactones and ranging from 70% to 100%.
