1572-97-0Relevant articles and documents
Resolution of (R,S)-1-(4-methoxyphenyl)ethanol by lipase-catalyzed stereoselective transesterification and the process optimization
He, Bingbing,Tang, Fengci,Sun, Chenrui,Su, Jiahao,Wu, Bingcheng,Chen, Yan,Xiao, Yuquan,Zhang, Panliang,Tang, Kewen
, p. 438 - 445 (2021/12/17)
An efficient lipase-catalyzed stereoselective transesterification reaction system was established for resolution of 1-(4-methoxyphenyl)ethanol (MOPE) enantiomers. A series of lipases were tested and compared. The immobilized lipase Novozym 40086 is selected as the best choice. The effects of organic solvent, acyl donor, time and temperature on substrate conversion (c), and optical purity of the remaining substrate (eeS) were investigated. Response surface methodology and central composite design were employed to evaluate the effect of some important factors and to optimize the process. Under the optimized conditions including solvent of n-hexane, acyl donor of vinyl acetate, temperature of 35°C, substrate molar ratio of 1:6, enzyme dosage of 20 mg, and reaction time of 2.5 h, eeS of 99.87% with c of 56.71% is achieved. The use of alkane solvent and immobilized enzyme, the mild reaction conditions, and the reduced reaction time make the system promising in industrial application.
Amino Acid-Functionalized Metal-Organic Frameworks for Asymmetric Base–Metal Catalysis
Newar, Rajashree,Akhtar, Naved,Antil, Neha,Kumar, Ajay,Shukla, Sakshi,Begum, Wahida,Manna, Kuntal
supporting information, p. 10964 - 10970 (2021/03/29)
We report a strategy to develop heterogeneous single-site enantioselective catalysts based on naturally occurring amino acids and earth-abundant metals for eco-friendly asymmetric catalysis. The grafting of amino acids within the pores of a metal-organic framework (MOF), followed by post-synthetic metalation with iron precursor, affords highly active and enantioselective (>99 % ee for 10 examples) catalysts for hydrosilylation and hydroboration of carbonyl compounds. Impressively, the MOF-Fe catalyst displayed high turnover numbers of up to 10 000 and was recycled and reused more than 15 times without diminishing the enantioselectivity. MOF-Fe displayed much higher activity and enantioselectivity than its homogeneous control catalyst, likely due to the formation of robust single-site catalyst in the MOF through site-isolation.
Synthesis, characterization and catalytic performance in enantioselective reactions by mesoporous silica materials functionalized with chiral thiourea-amine ligand
G?k, Ya?ar,G?k, Halil Zeki
, p. 853 - 874 (2020/11/10)
Chiral heterogeneous catalysts have been synthesized by grafting of silyl derivatives of (1R, 2R)- or (1S, 2S)-1,2-diphenylethane-1,2-diamine on SBA-15 mesoporous support. The mesoporous material SBA-15 and so-prepared chiral heterogeneous catalysts were characterized by a combination of different techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area. Results showed that (1R, 2R)- and (1S, 2S)-1,2-diphenylethane-1,2-diamine were successively immobilized on SBA-15 mesoporous support. Chiral heterogeneous catalysts and their homogenous counterparts were tested in enantioselective transfer hydrogenation of aromatic ketones and enantioselective Michael addition of acetylacetone to β-nitroolefin derivatives. The catalysts demonstrated notably high catalytic conversions (up to 99%) with moderate enantiomeric excess (up to 30% ee) for the heterogeneous enantioselective transfer hydrogenation. The catalytic performances for enantioselective Michael reaction showed excellent activities (up to 99%) with poor enantioselectivities. Particularly, the chiral heterogeneous catalysts could be readily recycled for Michael reaction and reused in three consecutive catalytic experiments with no loss of catalytic efficacies.
