RESUMEN
Herein, we developed a palladium-catalysed C-H cyclisation of benzoic acids in chlorobenzene without additional oxidants. The key to the success of these reactions is the use of chlorobenzene, which serves a dual role as a solvent and an oxidant, thus providing a simple and efficient method for synthesising phthalides.
RESUMEN
Gold(I)-catalyzed heteroannulation affords the efficient and straightforward construction of heterocyclic compounds. Herein, we developed a gold(I)-catalyzed heteroannulation of salicylic amides with alkynes producing a broad range of 1,3-benzoxazin-4-ones. The utility of this protocol was highlighted by synthesizing variously substituted benzoxazinones containing quaternary carbon centers, showing a high functional group tolerance and excellent atom economy of the thus introduced reaction course.
RESUMEN
The direct and selective functionalization of inert C-H bonds via intramolecular hydrogen atom transfer (HAT) is an increasingly powerful tool in organic synthesis. Herein, we designed an efficient and facile iodine atom transfer in fluorinated alkyl iodides via 1,5-HAT. Our process enables site-selective iodination of unreactive C(sp3)-H bonds to afford di- and tri-fluorinated alkyl iodides in good yields. Furthermore, our process shows excellent atom economy and high functional group tolerance, including methyl, methoxy, chloro, cyano, and silyl moieties.
RESUMEN
Herein, we designed a simple nitrile synthesis from N-[(2-nitrophenyl)sulfonyl]benzamides via base-promoted intramolecular nucleophilic aromatic substitution. The process features redox-neutral conditions as well as no requirement of toxic cyanide species and transition metals. Our process shows broad scope and various functional group compatibility, affording a variety of (hetero)aromatic nitriles in good to excellent yields.
Asunto(s)
Elementos de Transición , NitrilosRESUMEN
In this paper Pd-catalyzed intramolecular dehydrogenative C(sp3)-H amidation for the synthesis of isoindolinones is described. This method features the use of a Pd/C catalyst and the addition of a stoichiometric amount of oxidant is not necessary. A mechanistic study suggested the possible formation of H2 gas during the reaction.
RESUMEN
An asymmetric thia-Michael addition of arylthiols to α,ß-unsaturated carboxylic acids using a thiourea catalyst that bears arylboronic acid and tertiary amine moieties is reported. Both enantiomers of the Michael adducts can be obtained in high enantioselectivity and good yield merely by changing the solvent. The origin of the chirality switch in the products was examined in each solvent via spectroscopic analyses.
RESUMEN
Monodisperse molecularly imprinted polymers (MIPs) for promazine derivatives [promazine (PZ), methylpromazine (MPZ), chlorpromazine (CPZ) and bromopromazine (BPZ)], MIPPZ, MIPMPZ, MIPCPZ and MIPBPZ, were prepared using methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate as a crosslinker by multi-step swelling and polymerization. The retention and molecular-recognition properties of the obtained MIPs were evaluated using LC in hydrophilic interaction chromatography (HILIC) and reversed-phase modes. In computational approaches, intermolecular interaction modes and energies between PZ derivatives and MAAs were evaluated at the HF/6-311G(d,p) level. The interaction energies of PZ, MPZ, CPZ and BPZ with 4 equivalents of MAAs were calculated. The results indicated that the interaction of the aliphatic amine moiety of a PZ derivative with MAA gave almost similar interaction energies at the HF/6-311G(d,p) level, and that the interaction of the sulfur atom of a phenothiazine scaffold with MAA was also the case. The third interaction of the aromatic amine of a PZ derivative with MAA was in the order of MPZâ¯>â¯PZâ¯>â¯CPZâ¯>â¯BPZ presumably due to the change of basicity by the electron-donating or electron-withdrawing effect of a subsituent. Furthermore, the fourth attractive modes of CPZ and BPZ were suggested to be the interaction of their halogen atoms with MAA through both halogen bonding and hydrogen bonding, while PZ and MPZ were suggested to have the weak C-H â â â π interaction with MAA. In HILIC mode, the interaction energies at the HF method had good correlation with the retention factor of a PZ derivative on each MIP, indicating that in addition to the shape recognition, the attractive electrostatic interactions would be more responsible for its retention rather than the dispersion energies. Furthermore, in addition to the shape recognition, ionic and hydrophobic interactions, and halogen bonding and hydrogen bonding (the last interaction seems to be weak) seem to work for the retention and molecular-recognition of PZ derivatives on the MIPs in reversed-phase mode.
RESUMEN
A palladium-catalyzed highly selective intramolecular C-H aminocarbonylation of Br-functionalized phenethylamines in the presence of CO was achieved while leaving the C-Br bond unreacted to afford six-membered benzolactams with good to high yields. The remaining C-Br group in the cyclized product was successfully used as a reactive center for further functionalization through various palladium-catalyzed coupling reactions.
RESUMEN
Catalytic synthesis of indole-3-carboxamides from 2-ethynylanilines and isocyanates was achieved in the presence of a rhodium catalyst through a tandem-type, cyclization-addition sequence. This tandem-type process can be performed under mild reaction conditions, affording 2,3-disubstituted indoles in a one-pot manner generally in good to excellent yields. The broad substrate scope and good functional group compatibility make the method highly efficient and widely applicable, providing a facile and entirely novel route toward variously substituted indole-3-carboxamides.
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Acetileno/análogos & derivados , Compuestos de Anilina/química , Indoles/síntesis química , Isocianatos/química , Rodio/química , Acetileno/química , Catálisis , Técnicas Químicas Combinatorias , Ciclización , Indoles/química , Estructura MolecularRESUMEN
A new type of O-alkylation of 2-hydroxy-1,4-naphthoquinone with alkoxymethyl chlorides is described. The reaction course can be controlled by the choice of base and yields O-alkylated or O-alkoxymethylated products in high yield with high selectivity.
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Naftoquinonas/química , Alquilación , Compuestos Heterocíclicos/química , Éteres Metílicos/química , Naftoquinonas/síntesis químicaRESUMEN
Mercury pollution poses a severe threat to human health. To remove Hg(2+) from contaminated water, we synthesized Hg(2+)-trapping beads that include oligo-thymidine functionalities that can form thymine-Hg(II)-thymine base pairs on the solid support. The beads can selectively trap Hg(2+) even in the presence of other metal cations. More interestingly, Hg(2+)-trapping efficiency was higher in the presence of the co-existing cations. Thus, the developed Hg(2+)-trapping beads can capture Hg(2+) without affecting the mineral balance of water so much. The Hg(2+)-trapping beads presented here show promise for removing Hg(2+) from environmental water.
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Mercurio/química , Timina/química , Contaminantes Químicos del Agua/química , Emparejamiento Base , Oligonucleótidos/síntesis química , Oligonucleótidos/químicaRESUMEN
The efficient synthesis of functionalized enamines including ß-enaminoesters was effectively accomplished by the direct condensation of functionalized sp(3) carbanions such as acetates with formamides using in situ generated HMDS base from catalytic cesium fluoride and stoichiometric tristrimethylsilylamine.
Asunto(s)
Aminas/síntesis química , Carbono/química , Formamidas/química , Compuestos de Organosilicio/química , Aminas/química , Catálisis , Teoría CuánticaRESUMEN
Herein, we describe our development of synthetic methods for heterocyclic compounds based on the palladium-catalyzed carbon-hydrogen bond (C-H) functionalization/intramolecular carbon-heteroatom (nitrogen or sulfur) bond formation process. By this C-H cyclization method, we efficiently prepared various N-heterocycles, including indazoles, indoles, and 2-quinolinones, as well as S-heterocycles such as benzothiazoles and benzo[b]thiophenes. Yields are typically good to high and good functional-group tolerance is observed for each process, thereby indicating that the method provides a novel, highly applicable synthetic route to the abovementioned biologically important heterocyclic frameworks. As an application of this approach, an auto-tandem-type, one-pot process involving the oxidative Heck reaction and subsequent C-H cyclization using cinnamamides and arylboronic acids as starting materials in the presence of a palladium catalyst was also developed for the rapid construction of the 2-quinolinone nucleus.
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Compuestos Heterocíclicos/síntesis química , Paladio/química , Benzotiazoles/síntesis química , Benzotiazoles/química , Carbono/química , Catálisis , Ciclización , Compuestos Heterocíclicos/química , Hidrógeno/química , Indazoles/síntesis química , Indazoles/química , Indoles/síntesis química , Indoles/química , Quinolonas/síntesis química , Quinolonas/química , Tiofenos/síntesis química , Tiofenos/químicaRESUMEN
Catalytic carbonylative C-H cyclization of 2-arylphenols can be achieved in the presence of a ruthenium-based catalytic system. The process proceeds efficiently under balloon pressure of CO and produces variously substituted 6H-dibenzo[b,d]pyran-6-one compounds, typically in good to high yields. Functional groups such as the alkoxycarbonyl and acetyl groups as well as halogen atoms (F, Cl, and Br) are well tolerated during the reaction.
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Fenoles/química , Pironas/síntesis química , Catálisis , Ciclización , Enlace de Hidrógeno , Lactonas , Estructura Molecular , Fenantrenos , Pironas/química , RutenioRESUMEN
Organocatalytic functionalization of heteroaromatic N-oxides was investigated using in situ generated onium amide bases, and C-nucleophiles were efficiently introduced by the sequential addition-elimination reaction under metal-free conditions, affording 2-substituted nitrogen heteroaromatics generally in good to high yields.
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Amidas/química , Compuestos Heterocíclicos/química , Óxidos de Nitrógeno/química , Compuestos Onio/química , CatálisisRESUMEN
The facile syntheses of a variety functionalized propiolic acids were achieved by carboxylation of alkynylsilanes with carbon dioxide mediated by cesium fluoride under ambient conditions.
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Alquinos/química , Dióxido de Carbono/química , Cesio/química , Dimetilsulfóxido/química , Fluoruros/química , Propionatos/química , Silanos/químicaRESUMEN
Onium amides, generated in situ from the combination of aminosilanes and onium fluorides (R(4)PF, R(4)NF), are employed for the first time as bases for catalytic deprotonative functionalization of C(sp(2))-H and activated C(sp(3))-H bonds under mild conditions.
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Amidas/química , Compuestos Onio/química , Amidas/síntesis química , Catálisis , Enlace de Hidrógeno , Estructura Molecular , Compuestos Onio/síntesis química , ProtonesRESUMEN
In this study, a facile synthesis of 3-carboxylated indoles involving a tandem-type cyclization of 2-ethynylanilines and subsequent CO2 fixation at the 3-position of the indole ring is realized. The reaction proceeds efficiently at 65 °C under 10 atm of CO2, giving rise to variously substituted 3-carboxylated indoles, generally in high yields. An inorganic base, such as K2CO3, is the only reagent required, and the addition of transition metal catalysts is not necessary. The method provides a novel, simple, and promising strategy for CO2 fixation in the research field of heterocyclic chemistry.
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Compuestos de Anilina/química , Dióxido de Carbono/química , Ácidos Carboxílicos/síntesis química , Indoles/síntesis química , Ácidos Carboxílicos/química , Catálisis , Técnicas Químicas Combinatorias , Ciclización , Indoles/química , Estructura MolecularRESUMEN
A novel catalytic method for synthesizing 4-aryl-2-quinolinones is reported. The process involves two mechanistically independent, sequential Pd(II)-catalyzed reactions--the oxidative Heck reaction and the intramolecular C-H amidation--both of which smoothly proceed in the presence of a single catalytic system in a one-pot manner.
Asunto(s)
Amidas/química , Carbono/química , Hidrógeno/química , Paladio/química , Quinolonas/química , Catálisis , Oxidación-ReducciónRESUMEN
The coupling reaction of aryl iodides with arylboronic acids to give biaryl compounds can be efficiently performed without adding a transition metal catalyst. The key to success is the use of dimethyl carbonate as a solvent. This finding provides a new strategy for constructing a biaryl linkage.