This work reports gold‐catalyzed [4+3]‐annulations of 2‐(1‐alkynyl)‐2‐alken‐1‐ones with anthranils to yield epoxybenzoazepine products with excellent exo‐diastereoselectivity (dr>25:1). The utility of this new gold catalysis is manifested by applicable substrates over a broad scope. More importantly, the enantioselective versions of these [4+3]‐cycloadditions have been developed satisfactorily with chiral gold catalysts under ambient conditions (DCM, 0 °C); the ee levels range from 88.0–99.9 %. With DFT calculations, we postulate a stepwise pathway to rationalize the preferable exo‐stereoselection.
We report herein a highly efficient Cucatalyzed protocol for the conversion of aliphatic carboxylic acids to the corresponding difluoromethylated analogues. This robust, operationally simple and scalable protocol tolerates a variety of functional groups and can convert a diverse array of acid-containing complex molecules to the alkyl-CF 2 H products. Mechanistic studies support the involvement of alkyl radicals.
To build a carbon-neutral energy cycle, the development of electrocatalysts that can reduce CO 2 into products containing at least two carbon atoms (C 2+ ) is crucial. This process would require at least one C−C coupling of two C 1 intermediates. The (110) facet of copper is known for its ability to reduce CO 2 to C 2+ products in high quantities (Faradaic efficiency ≥65%). In this study, we used constant electrode potential density functional theory calculations to determine the dominant C−C coupling pathways for CO 2 electrochemical reduction (CO 2 ER) on Cu(110). By studying the mechanism of CO 2 ER to methane, we identified *CO and *CH as high-concentration C 1 species due to their high ΔG ‡ for further hydrogenation. Based on this result, 26 C−C coupling reactions that contain at least one high-concentration C 1 intermediate were selected for investigation. The most important ones responsible for C 2+ formation on Cu(110) were identified, and the influence of strain on the rates of these reactions was also investigated.
Developing processes that allow partial oxidation of light alkanes (C 1 −C 4 ) to more valuable oxygenates is important from both industrial and academic perspectives. In this study, quantum mechanics combined with a constant potential model were employed to evaluate the ability of metal-N 4 -functionalized graphene (gMN 4 ) to catalyze anodic partial oxidation of light alkanes to oxygenates via electrochemical means while considering both reactivity and selectivity. During the reaction, reactive oxo (*O) is generated through water electrochemical oxidation. This reactive oxo is used to oxidize light alkanes (represented by methane and propane). On the basis of investigating the systems with different Ms (Cr, Mn, Fe, Co, Ru, Rh, Os, and Ir) in a wide range of electrode potentials (U, 0.0− 2.5 V SHE ) and pH values (0.0−14.0), only gIrN 4 and gFeN 4 were capable of catalyzing this oxidation with acceptable reaction rates. The other catalysts were unable to form *O or inert to C−H bonds. Both alkanes can be oxidized but the rate for methane is slower. gIrN 4 oxidizes methane to formaldehyde under proper Us. For propane, this catalyst generates iso-propanol at low Us and acetone at high Us. gFeN 4 only oxidizes propane to acetone. Our theoretical investigation along with known experimental results suggest a high probability for experimental realization of this anodic partial oxidation, which would allow for utilization of natural gas discovered in remote oil fields.
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