59-47-2Relevant articles and documents
Ligand-Free Copper-Catalyzed Ullmann-Type C?O Bond Formation in Non-Innocent Deep Eutectic Solvents under Aerobic Conditions
Capriati, Vito,García-álvarez, Joaquín,Marinò, Manuela,Perna, Filippo M.,Quivelli, Andrea Francesca,Vitale, Paola
, (2021/12/09)
An efficient and novel protocol was developed for a Cu-catalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [CuI or CuII species] loading up to 5 mol% and K2CO3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70–96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E-factor as low as 5.76.
MnIII Porphyrins: Catalytic Coupling of Epoxides with CO2 under Mild Conditions and Mechanistic Considerations
Milani, Jorge L. S.,Meireles, Alexandre M.,Bezerra, Werberson A.,Martins, Dayse. C. S.,Cangussu, Danielle,das Chagas, Rafael P.
, p. 4393 - 4402 (2019/08/01)
A series of 5,10,15,20-tetrakis(2,3-dichlorophenyl)porphyrinate complexes of manganese(III) [MnIII(T2,3DCPP)X] with six different axial ligands (X=NO3 ?, AcO?, IO3 ?, Br?, Cl?, HO?) were investigated as catalysts in the cycloaddition reactions of CO2 and styrene oxide (SO), under mild conditions, i. e., atmospheric pressure and 60 °C. [MnIIIT(2,3DCPP)IO3] showed the best catalytic performance, selectively producing the respective cyclic carbonate from diverse epoxides using tetrabutylammonium bromide as a nucleophile source. Mechanistic considerations were inferred from electronic spectra and spectrophotometric titrations, showing that there are a series of equilibriums involved in the formation of the catalytic active species. Stability constants for the proposed equilibrium models were determined using SQUAD software. A catalytic cycle has been proposed based on those observations.
Stereoselective Hydrolysis of Epoxides by reVrEH3, a Novel Vigna radiata Epoxide Hydrolase with High Enantioselectivity or High and Complementary Regioselectivity
Hu, Die,Tang, Cunduo,Li, Chuang,Kan, Tingting,Shi, Xiaoling,Feng, Lei,Wu, Minchen
, p. 9861 - 9870 (2017/11/22)
To provide more options for the stereoselective hydrolysis of epoxides, an epoxide hydrolase (VrEH3) gene from Vigna radiata was cloned and expressed in Escherichia coli. Recombinant VrEH3 displayed the maximum activity at pH 7.0 and 45 °C and high stability at pH 4.5-7.5 and 55 °C. Notably, reVrEH3 exhibited high and complementary regioselectivity toward styrene oxides 1a-3a and high enantioselectivity (E = 48.7) toward o-cresyl glycidyl ether 9a. To elucidate these interesting phenomena, the interactions of the three-dimensional structure between VrEH3 and enantiomers of 1a and 9a were analyzed by molecular docking simulation. Using E. coli/vreh3 whole cells, gram-scale preparations of (R)-1b and (R)-9a were performed by enantioconvergent hydrolysis of 100 mM rac-1a and kinetic resolution of 200 mM rac-9a in the buffer-free water system at 25 °C. These afforded (R)-1b with >99% eep and 78.7% overall yield after recrystallization and (R)-9a with >99% ees, 38.7% overall yield, and 12.7 g/L/h space-time yield.