RESUMO
This work reports a method for the catalytic synthesis of C(3) SCF3-substituted pyrrolidinindoline using a small-ring organophosphorus-based catalyst and a hydrosilane reductant, with trifluoromethanesulfonyl chloride as the electrophilic SCF3 reagent. This method can drive the conversion of tryptamine to the C(3) SCF3-substituted pyrrolidine indoline. The readily available, inexpensive trifluoromethanesulfonyl chloride could be activated as an electrophilic SCF3 source by PIII/PV redox catalysis and could efficiently participate in the reaction of tryptamines, thus providing various substituted C(3) SCF3-substituted pyrrolidinoindoline in moderate to excellent yields. This presented strategy features a broad substrate scope, and the structure has value for in-depth research.
RESUMO
A metal-free and thiol-free organophosphorus-catalyzed method for forming thioethers was disclosed, driven by PIII/PVâO redox cycling. In this work, one-step dehydroxylative thioetherification of alcohols was fulfilled with various hypervalent organosulfur compounds. This established strategy features an excellent functional group tolerance and broad substrate scope, especially inactivated alcohols. The scale-up reaction and further transformation of the product were also successful. Additionally, this method offers a protecting-group-free and step-efficient approach for synthesizing peroxisome proliferator-activated receptor agonists which exhibited promising potential for treating osteoporosis in mammals.
RESUMO
An efficient and environmentally friendly synthetic approach to prepare thiazolidine-2-imine and oxazolidine-2-one derivatives has been developed. Thiazolidine-2-imines are synthesized in good to excellent yields by [3 + 2] annulation of p-quinamines with isothiocyanates under catalyst- and solvent-free conditions. Oxazolidine-2-ones are produced in good to excellent yields via [3 + 2] annulation of p-quinamines with CO2 using triethylenediamine (DABCO) as an organocatalyst. Furthermore, this strategy can be performed on a gram scale and tolerate a wide range of functional groups.
RESUMO
A green method to construct C-S bonds using sulfonyl chlorides and alcohols/acids via a PIII/PVâO catalytic system is reported. The organophosphorus-catalyzed umpolung reaction promotes us to propose the "dual-substrate deoxygenation" strategy. Herein, we adopt the "dual-substrate deoxygenation" strategy, which achieves the deoxygenation of sulfonyl chlorides and alcohols/acids to synthesize thioethers/thioesters driven by PIII/PVâO redox cycling. The catalytic method represents an operationally simple approach using stable phosphine oxide as a precatalyst and shows broad functional group tolerance. The potential application of this protocol is demonstrated by the late-stage diversification of drug analogues.
Assuntos
Compostos Organofosforados , Catálise , Oxigênio/química , Álcoois/química , Ácidos/química , Compostos Organofosforados/químicaRESUMO
A series of indole-fused scaffolds and derivatives was synthesized via the cyclization reaction of 2-indolylmethanols with azonaphthalene. These reactions were realized under mild reaction conditions through catalyst control, providing structurally diverse indole derivatives with moderate to excellent yields. This protocol also shows good substrate adaptability, especially in six-membered ring products.
Assuntos
Indóis , Catálise , CiclizaçãoRESUMO
A copper-mediated cyclization and dimerization of indole derived oxime acetate was developed to generate a series of biimidazo[1,2-a]indole scaffolds with two contiguous stereogenic quaternary carbons in one step.
Assuntos
Cobre , Indóis , Acetatos , Catálise , Ciclização , Dimerização , Estrutura Molecular , OximasRESUMO
We disclosed a novel water-soluble photocatalyst that could promote aerobic oxidative hydroxylation of arylboronic acids to furnish phenols in excellent yields. This transformation uses visible-light irradiation under environmentally friendly conditions, that is, water-soluble catalyst, metal-free, green oxidant, room temperature.
RESUMO
A formal [4 + 2] cycloaddition reaction of 1,3-disubstituted indoles and alkylquinones was realized to furnish polycyclic indolines in good yields. This protocol proceeded smoothly under basic conditions, with high atom-economy and broad substrate scope.
RESUMO
Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2'-dihydroxy-1,1'-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.
Assuntos
Naftóis/química , Catálise , Técnicas de Química Sintética , Fenóis/química , Ácidos Fosfóricos/química , Quinonas/química , EstereoisomerismoRESUMO
Bridged indoline derivatives were synthesized by an intermolecular Pd-catalyzed allylic dearomatization reaction of substituted indoles. The reaction between indoles and allyl carbonates bearing a nucleophilic alcohol side-chain proceeds in a cascade fashion, providing bridged indolines in excellent enantioselectivity.
RESUMO
We have developed Pd-catalyzed intermolecular Friedel-Crafts-type allylic alkylation and allylic dearomatization reactions of substituted indoles bearing a nucleophilic group with vinyloxirane, providing an efficient method to synthesize structurally diverse tetrahydrocarboline and spiroindolenine derivatives under mild conditions.
RESUMO
An organic acid catalyzed direct arylation of aromatic C(sp(2))-H bonds in phenols and naphthols for the preparation of 1,1'-linked functionalized biaryls was developed. The products are non-C2-symmetrical, atropoisomeric, and represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, is readily scaled up (up to 98â mmol), and the structurally diverse 2,2'-dihydroxy biaryl (i.e., BINOL-type), as well as 2-amino-2'-hydroxy products (i.e., NOBIN-type) are formed with complete regioselectivity. Density-functional calculations suggest that the quinone and imino-quinone monoacetal coupling partners are exclusively arylated at their α-position by an asynchronous [3,3]-sigmatropic rearrangement of a mixed acetal species which is formed inâ situ under the reaction conditions.
Assuntos
Hidrocarbonetos/síntese química , Compostos Orgânicos/química , Cristalografia por Raios X , Hidrocarbonetos/químicaRESUMO
A concise synthesis of spiroindolenines from 2-substituted (Me, Et) indoles and 2-(pyrrolidin-1-yl)benzaldehydes has been developed via a [1,5]-hydride shift/cyclization sequence. This method features a wide substrate scope and an operationally simple procedure, affording the spiroindolenines in good to excellent yields and moderate diastereoselectivity (3.5/1 dr). When the inseparable mixture of spiroindolenine isomers were washed with isopropyl ether after flash chromatography, the major isomers could be obtained in up to >20/1 dr.
Assuntos
Benzaldeídos/química , Indóis/química , Catálise , Ciclização , Ligação de Hidrogênio , Estrutura Molecular , EstereoisomerismoRESUMO
Expeditious access to oxadiazepines via 1,5-hydride shift/cyclization of pyrrolidine- or tetrahydroisoquinoline-containing nitrones has been developed. With 1,3-dipole nitrones serving as the hydride acceptors, this transformation was promoted by a Lewis acid, providing access to structurally diverse oxadiazepines in good yields. A one-pot process for in situ nitrone formation, a 1,5-hydride shift, and ring cyclization was also realized.
RESUMO
A practical and efficient stereoselective synthesis of arylglycine derivatives was realized via palladium-catalyzed α-arylation of a chiral nickel(II) glycinate complex with aryl bromides. The structurally diverse arylglycine products were obtained in excellent isolated yields and with good diastereoselectivity. A simple acidic hydrolysis furnished optically pure arylglycines in high yield, and the chiral ligand (S)-BPB could be efficiently recovered and reused.
Assuntos
Glicina/síntese química , Níquel/química , Compostos Organometálicos/química , Paládio/química , Catálise , Glicina/análogos & derivados , Glicina/química , Conformação Molecular , EstereoisomerismoRESUMO
Palladium-catalyzed asymmetric intramolecular Friedel-Crafts type allylic alkylation reaction of phenols was developed under mild conditions. In the presence of Pd2(dba)3 with (1R,2R)-DACH-phenyl Trost ligand (L2) in toluene at 50 °C, the reaction provides various C4 substituted tetrahydroisoquinolines with moderate to excellent yields, regioselectivity and enantioselectivity.
Assuntos
Paládio/química , Fenóis/química , Tetra-Hidroisoquinolinas/química , Alcaloides/química , Alquilação , Carbono/química , Catálise , Ligantes , Espectroscopia de Ressonância Magnética , Metais/química , Solventes/química , Estereoisomerismo , Especificidade por Substrato , Temperatura , Fatores de Tempo , Tolueno/química , Elementos de Transição/químicaRESUMO
O-aryloximes, generated from readily available and inexpensive oximes through transition-metal-free O-arylation, can either be hydrolyzed to O-arylhydroxylamines or conveniently converted to structurally diverse benzo[b]furans through an environmentally benign, one-pot [3,3]-sigmatropic rearrangement/cyclization sequence.
Assuntos
Benzofuranos/síntese química , Hidroxilamina/síntese química , Oximas/química , Benzofuranos/química , Ciclização , Hidroxilamina/química , Oximas/síntese químicaRESUMO
An efficient approach to synthesize N-aryl pyrroles via Lewis acid-mediated 1,5-hydride shift and isomerization of 2-(3-pyrroline-1-yl)arylaldehydes has been achieved in up to 89% yield. This methodology is applicable to the synthesis of fluorazene derivatives as electron donor (D)/acceptor (A) molecules.
Assuntos
Ácidos de Lewis/química , Pirróis/síntese química , Aldeídos/síntese química , Aldeídos/química , Catálise , Ciclização , Compostos Heterocíclicos com 3 Anéis/síntese química , Compostos Heterocíclicos com 3 Anéis/química , Isomerismo , Oxirredução , Pirróis/químicaRESUMO
We disclose an efficient and operationally simple protocol for the preparation of fused N-heterocycles starting from readily available 2-nitrobiaryls and PhMgBr under mild conditions. More than two dozen N-heterocycles, including two bioactive natural products, have been synthesized using this method. A stepwise electrophilic aromatic cyclization mechanism was proposed by DFT calculations.
Assuntos
Compostos Heterocíclicos/síntese química , Compostos Organometálicos/química , Aminação , Ciclização , Compostos Heterocíclicos/química , Estrutura Molecular , Teoria QuânticaRESUMO
Lewis acid-catalyzed redox-neutral amination of 2-(3-pyrroline-1-yl)benzaldehydes via intramolcular [1,5]-hydride shift/isomerization reaction has been realized, using the inherent reducing power of 3-pyrrolines. A series of N-arylpyrrole containing amines are obtained in high yields.