Catalytic and Stereoselective Glycosylation with a Novel and Efficient Disarmed Glycosyl Donor: Glycosyl<i>p</i>-Trifluoromethylbenzylthio-<i>p</i>-trifluoromethylphenyl Formimidate
efficient glycosyldonor having a p-trifluoro-methylbenzylthio-p-trifluoromethylphenyl formimidate function as a leaving group is easily prepared by the addition of anomeric hydroxyl group of 2,3,4,6-tetra-O-benzoyl-α,β-D-glucopyranose to p-trifluoromethylphenyl isothiocyanate, followed by treatment with p-trifluoromethylbenzyl bromide. Catalytic and stereoselectiveglycosylation using this glycosyl donor
Experimental studies and density functional theory (DFT) computations suggest that oxygen and proton reduction by decamethylferrocene (DMFc) in 1,2-dichloroethane involves protonated DMFc, DMFcH+, as an active intermediate species, producing hydrogen peroxide and hydrogen in aerobic and anaerobic conditions, respectively.
Light-Driven, Proton-Controlled, Catalytic Aerobic C–H Oxidation Mediated by a Mn(III) Porphyrinoid Complex
作者:Heather M. Neu、Jieun Jung、Regina A. Baglia、Maxime A. Siegler、Kei Ohkubo、Shunichi Fukuzumi、David P. Goldberg
DOI:10.1021/jacs.5b00816
日期:2015.4.15
The visible light-driven, catalytic aerobicoxidation of benzylicC-Hbonds was mediated by a Mn(III) corrolazine complex. To achieve catalytic turnovers, a strict selective requirement for the addition of protons was established. The resting state of the catalyst was unambiguously characterized by X-ray diffraction as [Mn(III)(H2O)(TBP8Cz(H))](+), in which a single, remote site on the ligand is protonated
可见光驱动的苄基 CH 键催化有氧氧化是由 Mn(III) corrolazine 络合物介导的。为了实现催化转换,建立了添加质子的严格选择要求。催化剂的静止状态通过 X 射线衍射明确表征为 [Mn(III)(H2O)(TBP8Cz(H))](+),其中配体上的单个远程位点被质子化。然而,如果两个远程站点被质子化,则与 O2 的反应性将被关闭。光谱方法表明,相关的 Mn(V)(O) 配合物也在 -60 °C 的相同远程位置质子化,但在升温时会发生价互变异构化。
Fine tuning of the catalytic effect of a metal-free porphyrin on the homogeneous oxygenreduction
作者:Antonín Trojánek、Jan Langmaier、Jakub Šebera、Stanislav Záliš、Jean-Michel Barbe、Hubert H. Girault、Zdeněk Samec
DOI:10.1039/c1cc11075f
日期:——
The reported catalytic effect of a metal-free porphyrin on the homogeneous dioxygen reduction is related to the competitive binding of dioxygen and the counteranion to the protonated free porphyrin base.
Structure of a Novel Rhodium Phosphinite Compound: Agostic Interactions as a Model for an Oxidative Addition Intermediate
作者:Sophia D. T. Cherry、Werner Kaminsky、D. Michael Heinekey
DOI:10.1021/acs.organomet.6b00418
日期:2016.6.27
Pincer ligand metalation is presumed to proceed via initial coordination to the phosphorus atoms followed by C–H oxidativeaddition. Few isolated intermediates in this process are known. A rhodium phosphinite complex has been isolated and structurally characterized that exhibits a strong agostic interaction with a C–H bond in the ligand backbone. The [(tBuPOCOP)Rh(CO)H]+ system exhibits greater acidity