The capacitance performance of a co-doped carbon-based supercapacitor derived from Ginkgo nuts was significantly enhanced by optimizing the mesoporous structure through high-temperature pyrolysis combined with KOH activation. The precisely engineered GBHHPC-750-4 is characterized by a hyper-crosslinked 3D hierarchical porous structure, with an exceptionally high specific surface area of 3163.9 m/g, a substantial mesopore proportion (Vmeso/Vt = 74.
View Article and Find Full Text PDFTransition metal catalyzed C-H bond activation has become one of the most important tools for constructing new chemical bonds. Introducing directing groups to the substrates is the key to a successful reaction, these directing groups can also be further transformed in the reaction. Amidines with their unique structure and reactivity are ideal substrates for transition metal-catalyzed C-H transformations.
View Article and Find Full Text PDFA versatile Ir(iii)-catalyzed C-H amidation of arenes by employing readily available and stable OH-free hydroxyamides as a novel amidation source. The reaction occurred with high efficiency and tolerance of a range of functional groups. A wide scope of aryl OH-free hydroxyzamides, including conjugated and challenging non-conjugated OH-free hydroxyzamides, were capable of this transformation and no addition of an external oxidant is required.
View Article and Find Full Text PDFA Rh(iii)-catalyzed cascade C-H activation/intramolecular cyclization of 3-aryl-5-isoxazolones with cyclic 2-diazo-1,3-diketones was described, leading to the formation of isoxazolo[2,3-f]phenanthridine skeletons. The protocol features the simultaneous one-pot formation of two new C-C/C-N bonds and one heterocycle in moderate-to-good yields with good functional group compatibility. It is amenable to large-scale synthesis and further transformation.
View Article and Find Full Text PDFAn efficient and practical one-pot strategy to produce highly substituted 1-naphthylamines via sequential palladium-catalyzed decarboxylative amination/intramolecular 6- benzannulation reactions has been described. In this reaction, a broad range of electron-rich, electron-neutral, and electron-deficient -alkynylarylketones react well with -hydroxyl aryl/alkylamides to give a diversity of 1-naphthylamines in good to excellent yields under mild reaction conditions. The gram-scale synthesis, with benefits such as undiminished product yield and easy transformation, illustrated the practicality of this method.
View Article and Find Full Text PDFA novel and mild Rh(iii)-catalyzed C-H activation/intramolecular condensation of 1-aryl-1H-pyrazol-5-amines with cyclic 2-diazo-1,3-diketones was developed, giving access to various important benzo[f]pyrazolo[1,5-a][1,3]diazepine scaffolds through sequential C-C/C-N bond formation in a one-pot procedure under additive- and oxidant-free conditions. Furthermore, 3-([1,1'-biphenyl]-2-ylamino)-2-ethoxycyclohex-2-enones can be obtained in good yields by constructing C-O and C-N bonds through 1,1'-insertion, dehydration, and isomerization processes.
View Article and Find Full Text PDFAn efficient rhodium-catalyzed construction of furo[2,3-]isochromene scaffolds through tandem double carbenoid insertion and diannulation of sulfoximine benzamides with α-diazo carbonyl compounds has been developed. Mechanistic studies revealed that the alkyl-rhodium intermediate generated by carbenoid insertion was directly trapped with another molecule of carbene species, followed by subsequent intramolecular cyclization reactions. Sulfoximine was released in situ, featuring a traceless directing fashion.
View Article and Find Full Text PDFA facile and efficient synthetic strategy for the chemoselective synthesis of N-substituted 3-aryl-1H-pyrazole derivatives has been developed, and it was oriented by different 2-diazo compounds. Both N-H insertion and Wolff-rearrangement products can be obtained selectively by the opportune choice of diazo compounds. N-Cyclohexenone 3-aryl-1H-pyrazoles were formed using cyclic 2-diazo-1,3-diketones via N-H insertion in the presence of a copper catalyst, and α-carbonyl 3-aryl-1H-pyrazoles could be synthesized through a Wolff-rearrangement process without any catalyst under thermal conditions.
View Article and Find Full Text PDFA simple, general route to the 2,3-dihydrobenzofurans substituted at C3 by an aryethynyl or aryl group, starting from propargylamine and its derivatives with benzoyl sulfonium salts, has been developed. This reaction involved an generated -quinone methide (-QM) intermediate followed by [4+1] annulation with sulfur ylides. Notably, this protocol's features include moderate to excellent yields and remarkable diastereoselectivity (>20:1 dr in general), easy performance, as well as applicability to versatile 2,3-dihydrobenzofurans with aryethynyl or an aryl group via C-C and C-O bond formation in one pot without any catalyst in an aqueous mixed solvent.
View Article and Find Full Text PDFA versatile and highly regioselective FeCl3-promoted tandem cyclization reaction of in situ generated alkynyl o-quinone methides (o-AQMs) with β-keto esters has been developed on the basis of the mode involving an intermolecular 1,4-conjugate addition/alkyne-allene isomerization/intramolecular transesterification/isomerization cascade. Using this method, a variety of diversely substituted 4-styryl-2H-chromen-2-ones were prepared with good efficiency and exclusive site-selectivity.
View Article and Find Full Text PDFA simple C-H/N-H bond functionalization of N-aryl amidines with cyclic 2-diazo-1,3-diketones for the synthesis of 1-aminoisoquinolines has been accomplished by employing [Cp*RhCl]/CsOPiv as the catalyst system. This methodology proceeds by a cascade C-H activation/intramolecular cyclization under mild reaction conditions, features a broad substrate scope, and involves the formation of two new σ bonds (C-C and C-N) in a single operation for the construction of novel 1-aminoisoquinoline skeletons in good to excellent yields.
View Article and Find Full Text PDFA Rh(III)-catalyzed C-H activation/cyclization cascade reaction is described. The reaction involves cyclic 2-diazo-1,3-diketones and -arylamides, and it proceeds via an intermolecular C-C bond formation and subsequent intramolecular C-N bond formation. A variety of -acyl-2,3-dihydro-1-carbazol-4(9)-ones were obtained under mild conditions in good to excellent yields (65-90%).
View Article and Find Full Text PDFA novel and efficient strategy for the synthesis of 2-hydroxy-6-oxocyclohex-1-enecarboxamides through a Rh(OAc)-catalyzed direct carboxamidation of cyclic 2-diazo-1,3-diketones has been developed. The method features readily available starting materials, easy scalability, mild reaction conditions and a simple work-up for product isolation, which makes this strategy highly attractive. A tentative mechanism involving an isocyanide insertion and hydrolysis sequence for this reaction is proposed.
View Article and Find Full Text PDFA mild and efficient Rh(III)-catalyzed C-H activation/esterification reaction for the synthesis of isocoumarins has been developed. This procedure uses readily available benzoic acids and cyclic diazo-1,3-diketones as starting materials and involves domino intermolecular C-H activation in combination with intramolecular esterification to give the corresponding isocoumarins in moderate to excellent yields. This process provides a facile approach for the construction of isocoumarins containing various functional groups that does not require any additives.
View Article and Find Full Text PDFA convenient and efficient synthesis of 2-arylimino-6,7-dihydrobenzo[][1,3]oxathiol-4(5)-ones was developed via a Rh(OAc)-catalyzed reaction of cyclic 2-diazo-1,3-diketones and aryl isothiocyanates in acetone at 60 °C. This reaction uses readily available stable cyclic 2-diazo-1,3-diketones as a starting material and generates the desired products in good to excellent yields (78-93%). The reaction proceeds under mild reaction conditions, produces only N as the byproduct, and features a broad substrate scope.
View Article and Find Full Text PDF