A copper-catalyzed [3 + 2] annulation of -acyl oximes with 2-electron-withdrawing group substituted -hydroquinones for the efficient synthesis of polysubstituted 5-hydroxyindoles is developed. Further intramolecular cyclization leads to the concise and rapid construction of several kinds of 3,4- and 4,5-fused polycyclic indoles.
View Article and Find Full Text PDFA copper-catalyzed [3 + 2] annulation of -acyl oximes with 4-sulfonamidophenols is developed. The advantage of this method lies in the concurrent double activation of two substrates to form nucleophilic enamines and electrophilic quinone monoimines. The substituent on the α-carbon of -acyl oxime determines two different reaction pathways, thereby leading to the selective generation of 5-sulfonamidoindoles and 2-amido-5-sulfonamidobenzofuran-3(2)-ones.
View Article and Find Full Text PDFOsteoarthritis (OA) is a degenerative disease that ultimately leads to joint deformity. The pathogenesis of OA is believed to involve abnormal chondrocyte death, with ferroptosis serving a key role in chondrocyte damage. The present study investigated whether acetyl zingerone (AZ), a newly identified antioxidant derived from curcumin, can alleviate the progression of OA.
View Article and Find Full Text PDFA copper-catalyzed [3+2] annulation of -acyl ketoximes with 2-aryl malonates for the concise synthesis of 3-aryl-4-pyrrolin-2-ones has been developed. The advantage of this method lies in the use of -acyl oximes as an internal oxidant to generate the nucleophilic enamines and electrophilic -quinone methides concurrently. The subsequent nucleophilic addition undergoes selectively on the α-C of malonates.
View Article and Find Full Text PDFA copper-catalyzed annulation of -acyl oximes with cyclic 1,3-diones has been developed for the concise synthesis of 7,8-dihydroindolizin-5(6)-ones and cyclohexanone-fused furans through the substituent-controlled selective radical coupling process. 2-Alkyl cyclic 1,3-diones undergo C-C radical coupling, while 2-unsubstituted cyclic 1,3-diones undergo C-O radical coupling.
View Article and Find Full Text PDFA copper-catalyzed annulation of -unsaturated -acyl ketoximes with isoquinolinium -ylides has been developed for the concise synthesis of stable N-H imines with a benzo[7,8]indolizine core. When β-(2-bromoaryl)--unsaturated -acyl ketoximes are used as the starting materials, a cascade cyclization occurs to afford the benzo[7,8]indolizino[1,2-]quinolines.
View Article and Find Full Text PDFA copper-catalyzed bisannulation reaction of malonate-tethered -acyl oximes with pyridine, pyrazine, pyridazine, and quinoline derivatives has been developed for the concise synthesis of structurally novel dihydroindolizine-fused pyrrolidinones and their analogues. The present reaction shows excellent regioselectivity and stereoselectivity. Theoretical calculations reveal that the coordination effect of the carbonyl group in the nucleophilic substrate determines the excellent regioselectivity.
View Article and Find Full Text PDFA copper-catalyzed cascade annulation of malonate-tethered -acyl oximes with cyclic 1,3-dicarbonyl compounds has been developed for the rapid synthesis of spiro-pentacyclic derivatives. This reaction allows the one-step formation of five C-C/N/O bonds and an angular tricyclic core under very mild conditions and shows excellent regioselectivity and stereoselectivity.
View Article and Find Full Text PDFA Cu(OAc)-promoted oxidative cross-dehydrogenative coupling reaction of α-acylmethyl malonates with indole derivatives was developed. In the case of indoles, the regioselective coupling products were formed through a sequential dehydrogenation-addition-dehydrogenation process. When a second nucleophilic center was located in the 2-position of indoles, further successive nucleophilic cyclization occurred to give polycyclic indole derivatives.
View Article and Find Full Text PDFA copper-catalyzed annulation of oxime acetates and α-amino acid ester derivatives for the easy preparation of 4-pyrrolin-2-ones bearing a 3-amino group has been developed. This process features the oxidation of amines with oxime esters as the internal oxidant to produce the active 1,3-dinucleophilic and 1,2-dielectrophilic species concurrently. The subsequent nucleophilic cyclization realizes the efficient construction of 4-pyrrolin-2-one derivatives.
View Article and Find Full Text PDFA catalytic asymmetric House-Meinwald rearrangement for the synthesis of both cyclic and acyclic ketones is disclosed. From readily accessible racemic tetrasubstituted epoxides, this approach provides efficient access to chiral ketones bearing α all-carbon quaternary stereocenters with high enantiocontrol. The observation of positive nonlinear effects and nontrivial kinetic feature provided important insights into the mechanism.
View Article and Find Full Text PDFCuI-catalyzed reaction of C with tertiary amines by using air as the sole oxidant has been developed. Spiro-linked methanofullerenes bearing cyclic amides and fullerenoalkanals can be obtained selectively using the cyclic and acyclic amines as starting materials, respectively. The reactions show a wide functional group tolerance.
View Article and Find Full Text PDFA Cu(OAc)-promoted cascade reaction of malonate-tetherd acyl oximes with indoles, indole-2-alcohols, or indole-2-carboxmides provides facile access to polysubstituted 3-pyrrolin-2-ones. The reaction features the generation of two adjacent electrophilic centers at the same time as cyclization to lactam. The subsequent double addition with nucleophiles followed by oxidation realizes the difunctionalization of the imine sp-carbon and the adjacent α-sp-carbon.
View Article and Find Full Text PDFA tunable copper-catalyzed reaction of C with 2-ethoxycarbonylacetamides using air as the oxidant has been explored, which selectively affords methanofullerenes (2) and dihydrofuran-fused fullerenes (3) under the CuI/DMAP and CuCl/NMI catalytic systems, respectively. Furthermore, the generated dihydrofuran-fused fullerenes could be transformed to fulleropyrrolidinones (4 and 5) upon treatment with BF·EtO.
View Article and Find Full Text PDFCuI-catalyzed diverse functionalizations of C with amino alcohols with aerobic oxygen as the sole oxidant have been explored. For 2-/3-amino alcohols, an aminooxygenation reaction occurs to generate fulleromorpholine and fullerooxazepane derivatives. When a tethered furan ring exists, a further intramolecular [4 + 2] reaction with the neighboring double bond occurs to furnish the cis-1 products.
View Article and Find Full Text PDFThe CsCO-catalyzed reaction of 2-oxindoles with enones affords 2,2-disubstituted indolin-3-ones through domino "Michael addition-oxidation-ring-cleavage-C-N coupling" process. O acts as the sole oxidant to accomplish the oxidative process. The indolin-3-ones can be further transformed to pyridazine, azirdine-fused 3-oxindoles, 4-quinolone derivatives easily.
View Article and Find Full Text PDFThe thermal reaction of C with aromatic aldehydes and inactive secondary amines for the stereoselective synthesis of trans-1,2,5-trisubstituted fulleropyrrolidines has been developed. Moreover, when an o-hydroxyl group was located at the phenyl ring of the generated fulleropyrrolidines, the Cu(OAc)-promoted regioselective intramolecular C-O coupling reaction occurred to generate unique tricycle-fused fullerene derivatives.
View Article and Find Full Text PDFThe Cu(OAc)2-mediated intermolecular diamination reaction of C60 with ureas allows the concise and efficient preparation of fulleroimidazolidinones involving the cleavage of two N-H bonds and formation of two C-N bonds. Both dialkylated and diarylated fulleroimidazolidinones can be synthesized using this method.
View Article and Find Full Text PDFA convenient approach for the synthesis of 1,4-diketones bearing an amino group has been developed through the K2CO3-catalyzed reaction of 2-oxindoles with enones with the assistance of atmospheric O2 via sequential Michael addition-oxidation-ring-cleavage process. The further intramolecular reaction leads to the formation of benzoazepinone, quinoline, and 3-oxindole derivatives.
View Article and Find Full Text PDFThe Cu(OAc)2-promoted reaction of C60 with easily available primary amines allows the concise preparation of aziridinofullerenes. Both alkyl and aryl amines are suitable in this reaction. Moreover, the Cu(OAc)2-promoted reaction of C60 with diamines affords C60-fused cyclic 1,2-diaminated fullerenes.
View Article and Find Full Text PDFThe Lewis base-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with various ureas allows the easy preparation of fulleroimidazolidinones with a high tolerance for functional groups. Alkyl-substituted ureas show better reactivity than aryl-substituted ureas.
View Article and Find Full Text PDFA hypervalent iodine-promoted intermolecular diamination reactions of C60 with sulfamides or phosphoryl diamides affords two classes of novel C60-fused cyclic sulfamide or phosphoryl diamide derivatives. The reaction between C60 and sulfamides can be effectively controlled to selectively synthesize diamination products or azafulleroids under PhIO/I2 or PhI(OAc)2/I2 conditions, respectively. Moreover, phosphoryl diamides were first used as an amine source in the diamination of alkenes.
View Article and Find Full Text PDFBF3·Et2O-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with sulfamides has been exploited for the easy preparation of cyclic sulfamide-fused fullerene derivatives. Moreover, the Lewis base catalyzed double amination of N-tosylaziridinofullerene, with amidines as the diamine source, is demonstrated for the first time. The present methods provide new routes to cyclic 1,2-diaminated [60]fullerenes.
View Article and Find Full Text PDFThe BF3·Et2O-catalyzed formal [3 + 2] reaction of aziridinofullerenes with various carbonyl compounds for the easy preparation of fullerooxazolidines has been developed. Moreover, the reaction of aziridinofullerene with ethyl formate affords the simplest fullerooxazole without substituent.
View Article and Find Full Text PDFThe hypervalent iodine reagent mediated reaction of C60 with various readily available amines for the easy preparation of iminofullerenes has been developed. The reaction between C60 and sulfonamides can be effectively controlled to selectively synthesize azafulleroids or aziridinofullerenes under PhI(OAc)2/I2 or PhIO/I2/CuCl/lutidine conditions, respectively. For phosphamide and urea, only one isomer is obtained.
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