18511-62-1Relevant articles and documents
Asymmetric Epoxidation of Olefins Catalyzed by Substituted Aminobenzimidazole Manganese Complexes Derived from L-Proline
Tian, Jing,Lin, Jin,Zhang, Jisheng,Xia, Chungu,Sun, Wei
supporting information, p. 593 - 600 (2021/11/16)
A family of manganese complexes [Mn(Rpeb)(OTf)2] (peb=1-(1-ethyl-1H-benzo[d]imidazol-2-yl)-N-((1-((1-ethyl-1H-benzo[d]imidazol-2-yl)methyl) pyrrolidin-2-yl)methyl)-N-methylmethanamine)) derived from L-proline has been synthesized and characterized, where R refers to the group at the diamine backbone. X-ray crystallographic analyses indicate that all the manganese complexes [Mn(Rpeb)(OTf)2] exhibit cis-α topology. These types of complexes are shown to catalyze the asymmetric epoxidation of olefins employing H2O2 as a terminal oxidant with up to 96% ee. Obviously, the R group of the diamine backbone can influence the catalytic activity and enantioselectivity in the asymmetric epoxidation of olefins. In particular, Mn(i-Prpeb)(OTf)2 bearing an isopropyl arm, cannot catalyze the epoxidation reaction with H2O2 as the oxidant. However, when PhI(OAc)2 is used as the oxidant instead, all the manganese complexes including Mn(i-Prpeb)(OTf)2 can promote the epoxidation reactions efficiently. Taken together, these results indicate that isopropyl substitution on the Rpeb ligand inhibits the formation of active Mn(V)-oxo species in the H2O2/carboxylic acid system via an acid-assisted pathway.
Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
Hou, Xiao-Dong,Hu, Bo-Chun,Hu, Die,Lei, Yu-Qing,Rao, Yi-Jian,Wu, Min-Chen,Zhang, Dong
supporting information, p. 1757 - 1761 (2022/03/16)
Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts to access 19 structurally diverse chiral monosubstituted epoxides (97.1 - ≥ 99% ees) and vicinal diols (56.2-98.0% eep) with high yields.
Synthesis of a light-harvesting ruthenium porphyrin complex substituted with BODIPY units. Implications for visible light-promoted catalytic oxidations
Malone, Jonathan,Klaine, Seth,Alcantar, Christian,Bratcher, Fox,Zhang, Rui
, p. 4977 - 4985 (2021/03/26)
A light-harvesting ruthenium porphyrin substituted covalently with four boron-dipyrrin (BODIPY) moieties has been synthesized and studied. The resulting complex showed an efficient decarbonylation reaction predominantly due to a photo-induced energy transfer process. Chemical oxidation of the ruthenium(ii) BODIPY-porphyrin afforded a high-energytrans-dioxoruthenium(vi) species that is one order of magnitude more reactive towards alkene oxidation than those analogues supported by conventional porphyrins. In the presence of visible light, the ruthenium(ii) BODIPY-porphyrin displayed remarkable catalytic activity toward sulfide oxidation and alkene epoxidation using iodobenzene diacetate [PhI(OAc)2] and 2,6-dichloropyridineN-oxide (Cl2pyNO) as terminal oxidants, respectively. The findings in this work highlight that porphyrin-BODIPY conjugated metal complexes are potentially useful for visible light-promoted catalytic oxidations.
