RESUMO
A copper-catalyzed cascade annulation of malonate-tethered O-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.
RESUMO
A Cu(OAc)2-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. The Cu(OAc)2 was proved to act as not only an oxidant but also a catalyst.
RESUMO
A 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.
RESUMO
CuI-catalyzed reaction of C60 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. In addition, four ([6,6]-phenyl-C61-butyric acid methyl ester) analogues can be easily prepared through the developed method.
RESUMO
A tunable copper-catalyzed reaction of C60 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 BF3·Et2O.
RESUMO
CuI-catalyzed diverse functionalizations of C60 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. In the case of 4-/5-amino alcohols, methanofullerenes linking with cyclic amides are obtained through cyclic enamine intermediates.
RESUMO
The Cs2CO3-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. O2 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.
RESUMO
The 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.
RESUMO
A 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.
RESUMO
The thermal reaction of C60 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)2-promoted regioselective intramolecular C-O coupling reaction occurred to generate unique tricycle-fused fullerene derivatives.
RESUMO
The 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.
RESUMO
The 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.
Assuntos
Aziridinas/síntese química , Fulerenos/química , Imidazolidinas/síntese química , Bases de Lewis/química , Ureia/química , Aziridinas/química , Catálise , Imidazolidinas/química , Modelos Moleculares , Estrutura MolecularRESUMO
BF3·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.
RESUMO
The 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.
Assuntos
Aziridinas/química , Compostos de Boro/química , Fulerenos/química , Oxazóis/química , Catálise , Estrutura MolecularRESUMO
A copper-catalyzed [3 + 2] annulation of O-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 O-acyl oxime determines two different reaction pathways, thereby leading to the selective generation of 5-sulfonamidoindoles and 2-amido-5-sulfonamidobenzofuran-3(2H)-ones.
RESUMO
One-step DMAP-catalyzed [3 + 2] and [4 + 2] cycloaddition reactions between C(60) and unmodified Morita-Baylis-Hillman adducts in the presence of Ac(2)O have been developed for the easy preparation of cyclopentene- and cyclohexene-fused [60]fullerene derivatives. When the MBH adducts bear an alkyl group, two different reaction pathways could be controlled selectively depending on the conditions.
Assuntos
Diacetil/análogos & derivados , Diacetil/química , Fulerenos/química , Catálise , Reação de Cicloadição , Estrutura Molecular , EstereoisomerismoRESUMO
We report here a convenient method to construct polysubstituted azetidines and 2,4-dioxo-1,3-diazabicyclo[3.2.0] compounds with high stereoselectivities in a one-pot reaction mediated by I2. The tetramethylguanidine (TMG)/I2-mediated formal [2 + 2] cycloaddition reaction of α-amidomalonate 1 with enones 2 affords functionalized azetidine derivatives 4 in moderate to good yields with high diastereoselectivity. When the α-ureidomalonate 5 is used instead of 1, 2,4-dioxo-1,3-diazabicyclo[3.2.0]heptanes 8 and 2,4-dioxo-1,3-diazabicyclo[3.2.0]heptenes 9 can be prepared selectively through the control of solvent and temperature. 2,4-Dioxo-1,3-diazabicyclo[3.2.0]heptanes 8 can further undergo ring-opening reactions with different nucleophilic reagents to afford the corresponding polyfunctionalized azetidine derivatives 13-16 with high steroselectivities.
Assuntos
Compostos Azabicíclicos/síntese química , Azetidinas/síntese química , Iodo/química , Compostos Azabicíclicos/química , Azetidinas/química , Ciclização , Reação de Cicloadição , Estrutura Molecular , EstereoisomerismoRESUMO
An I2-catalyzed hydroxylation of ß-dicarbonyl moieties using air as the oxidant under photoirradiation has been developed for the easy preparation of α-hydroxy-ß-dicarbonyl compounds. The transformation was completed with only 1 mol % of I2. With α-unsubstituted malonates, the hydroxylated dimerization product was afforded as the predominant product along with a minor product, α,α-dihydroxyl malonate.
Assuntos
Atmosfera/química , Iodo/química , Cetonas/química , Oxigênio/química , Álcoois/síntese química , Álcoois/química , Catálise , Hidroxilação , Processos FotoquímicosRESUMO
The CuCl2-mediated three-component reaction of C60 with amines and dimethyl acetylenedicarboxylate afforded the fulleropyrrolines in moderate yields. Furthermore, the CuCl2-mediated oxidative [2 + 1] reaction of C60 with aromatic amines bearing a strong electron-withdrawing group provided the aziridinofullerenes and the selective cis-1-bisaziridinofullerenes.
RESUMO
The 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. However, carbamate gives three kinds of products. Interestingly, the reaction of C60 with alkylamines allows the effective synthesis of aziridinofullerenes and regioselective cis-1-bisaziridinofullerenes.