Search

A highly efficient palladium-catalyzed allenamide allylic alkylation of sulfenate anions under mild conditions is demonstrated. The present methodology provides a practical protocol to access various sulfoxide-containing heterocyclic compounds. The salient features of this transformation include a broad substrate scope, good functional group tolerance, easy to scale-up, and ready synthetic transformation.

We have developed an efficient protocol for the construction of polycyclic dihydrobenzofuran spirooxindole scaffolds via base promoted cascade annulation of Morita-Baylis-Hillman (MBH) carbonates of isatins with

A DABCO-promoted annulation reaction of bindone ([1,2'-biindenylidene]-1',3,3'-trione) and 3-methyleneoxindoles showed very interesting molecular diversity under different reaction conditions. The base-promoted annulation reaction of bindone and 3-phenacylideneoxindoles in DCM at room temperature afforded spiro[indeno[1,2-a]fluorene-5,3'-indoline] derivatives in good yields and with high diastereoselectivity. However, the similar reaction of 2-(2-oxoindolin-3-ylidene) acetates resulted in Z/E-isomeric spiro[indeno[1,2-a]fluorene-5,3'-indolines] with diastereomeric ratios of 2:1 to 10:1. On the other hand, the DABCO-promoted annulation reaction of bindone and 3-methyleneoxindoles in acetonitrile at different temperatures selectively gave spiro[benzo[5,6]pentaleno[1,6a-b]naphthalene-7,3'-indoline] derivatives and complex dispiro[indoline-3,6'-[4b,6a]ethanoindeno[1,2-a]fluorene-14',3″-indolines] in satisfactory yields.

p-TsOH catalyzed Diels-Alder reaction of 2-(1-alkylindol-3-yl)naphthalene-1,4-diones and 3-phenacylideneoxindoles showed fascinating diastereoselectivity. The reaction with the hydrated p-TsOH afforded trans-isomers of dihydrospiro[indoline-3,6'-naphtho[2,3-c]carbazoles] as major products. Alternatively, the reaction with anhydrous p-TsOH under a Dean and Stark apparatus predominately gave cis-isomer of dihydrospiro[indoline-3,6'-naphtho[2,3-c]carbazoles]. On the other hand, the similar p-TsOH catalyzed reaction of 2-(indol-3-yl)naphthalene-1,4-diones with 3-arylideneindolin-2-ones afforded cis/trans-isomers of dihydrospiro[indoline-3,6'-naphtho[2,3-c]carbazoles]. Additionally, the p-TsOH catalyzed reaction of 2-(indol-3-yl)naphthalene-1,4-diones with 2-arylidene-1,3-indanediones gave the expected spiro[indene-2,6'-naphtho[2,3-c]carbazoles] in satisfactory yields.

In the presence of copper sulfate, the three-component reaction of aromatic aldehydes, ethylindole-3-acetate and 4-arylidene-5-methyl-2-phenylpyrazol-3-ones, in refluxing toluene afforded spiro[carbazole-3,4'-pyrazoles] in good yields with high diastereoselectivity. More importantly, the similar CuSO4 promoted the four-component reaction of two molecular aromatic aldehydes with ethylindole-3-acetate and 5-methyl-2-phenyl-pyrazol-3-one resulted in 2,4-diarylspiro[carbazole-3,4'-pyrazoles] in satisfactory yields. Additionally, CuSO4 promoted the four-component reaction of two molecular aromatic aldehydes, ethylindole-3-acetate and 2-phenylthiazol-4-one, in refluxing toluene gave 2,4-diarylspiro[carbazole-3,4'-thiazoles] with diastereomeric ratios in the range of 3:1 to 20:1.

A simple InBr3-catalyzed domino reaction of indoles, phenylacetylenes, and various 3-methyleneoxindolines in toluene is described. This reaction not only provided a convenient synthetic protocol fo...

Described herein is a stereo- and regioselective cis-hydrophosphorylation reaction of the internal alkyne of 1,3-enynes that accesses various 1,3-dienes in good isolated yields. The visible-light irradiation of NiCl2(PPh3)2 allows the generation of highly reactive nickel(II)-phosphorus species that subsequently migrate into the internal alkyne of the 1,3-enynes and protonate the resulting vinyl nickel species, leading to various phosphinoyl 1,3-butadienes under mild reaction conditions.

The three-component reaction of α,β-unsaturated N-arylaldimines, dialkyl but-2-ynedioates, and 2-arylidene Meldrum acids in DCM at room temperature gave mixtures of cis/trans-11-aryl-7-styryl-2,4-dioxa-8-azaspiro[5.5]undec-9-enes in satisfactory yields. The similar three-component reaction with 2-arylidene-N,N'-dimethylbarbituric acids afforded cis-11-phenyl-7-styryl-2,4,8-triazaspiro[5.5]undec-9-enes as major products. On the other hand, the three-component reaction of N-arylaldimines, dialkyl but-2-ynedioates, and 2-arylidene Meldrum acids or 2-arylidene-N,N'-dimethylbarbituric acids afforded cis/trans-isomeric spirocompounds in satisfactory yields with high diastereoselectivity. This domino [2+2+2] cycloaddition reaction proceeded with sequential nucleophilic addition of N-arylaldimine to an electron-deficient alkyne, Michael addition, and annulation process. The stereochemistry of all cis/trans isomeric spirocompounds was clearly elucidated by the determination of 33 single-crystal structures. The diastereoselectivity of the three-component reaction was correlated by DFT calculations.

A triethylamine-promoted domino reaction of three molecular 1,3-indanediones with various 3-methyleneoxindoles in refluxing ethanol has been developed. Series of novel polycyclic triindanone-fused spiro[bicyclo[2.2.2]octane-2,3'-indoline] derivatives were successfully synthesized in satisfactory yields with high diastereoselectivity. This domino reaction was accomplished with in situ generation of active cyclic dienes by base-promoted cyclotrimerization or cyclotetramerization of 1,3-indanediones and sequential Diels-Alder reaction of active cyclic dienes with dienophilic 3-methyleneoxindoles.

The three-component reaction of alkyl 2-(benzo[b][1,4]thiazin-3-ylidene)acetates, isatins, and 1,3-indanedione (1,3-cyclopentanedione) in ethanol in the presence of acetic acid conveniently afforde...

Triethylamine promoted the pseudo-five-component reaction of aromatic aldehyde with four molecules of 1,3-indanediones in refluxing ethanol to give unique polycyclic bicyclo[2.2.2]octane derivatives containing bridged- and spiro-indanone scaffolds in good yields. The mechanistic studies supported that the reaction included base-catalyzed cyclotrimerization of 1,3-indanedione to give an active cyclic diene and the sequential Diels-Alder reaction with in situ generated 2-arylidene-1,3-indanediones as electron-deficient dienophiles. On the other hand, the pseudo-four-component reaction of salicylaldehyde with 1,3-indanedione afforded the dibenzo[b,g]indeno[1',2':3,4]fluoreno[1,2-d]oxonines in high yields. This reaction clearly demonstrated the high efficiency, molecular convergence, atom-economy, and impressive selectivity of multicomponent reactions.

Pd-catalyzed asymmetric C–H bond activation for the synthesis of P-stereogenic dibenzophospholes was efficiently achieved via two types of catalytic systems. Chiral phosphoric amides/acids as ligan...

Described herein is a visible-light-driven chlorotrifluoromethylative and chlorotrichloromethylative cyclization reaction to synthesize chlorotrifluoromethylated and chlorotrichloromethylated cyclic compounds. Visible-light photochemistry was utilized to generate trifluoromethyl and trichloromethyl radicals and trigger radical addition/cyclization/chlorination sequences. The use of terminal alkene-derived enynes enables the regioselective and stereoselective synthesis of chlorotrifluoromethylated and chlorotrichloromethylated pyrrolidines, piperidines, and cyclopentanes.

The multicomponent reaction of l-proline, isatins, and excess of methyl propiolates in methanol unexpectedly afforded 2-(oxoindolin-3-ylidene)propylidene)pyrrolidin-1-yl)acrylates in good yields, and the products subsequently converted to unique nine-membered pyrrolo[1',2':1,9]azonino[6,5,4- cd]indoles in the presence of p-TsOH. Furthermore, the multicomponent reaction of l-proline, N-benzylisatins, and excess alkyl propiolates in refluxing chloroform unprecedentedly resulted in eight-membered azocino[1,2- a]benzo[ c][1,5]diazocines as the main product. The molecular structures of the polyheterocyclic compounds were confirmed by determination of 19 single crystal structures. The reaction mechanism was believed to contain the sequential 1,3-dipolar cycloaddition, addition of cyclic tertiary amine to excess of propiolate, and fascinating ring opening as well as rearrangement process. The N-substituent on isatins played a critical role in the different reaction patterns.

An efficient and diastereoselective synthetic protocol for the construction of spiro[cyclohexane-1,3′-indolin]-3-en-2′-ones and spiro[cyclohexane-1,2′-inden]-3-ene-1′,3′-diones was provided by HOAc-mediated domino reaction of pinacoles with typical dienophiles, such as 3-methyleneoxindolines and 2-arylideneindane-1,3-diones, in ionic liquid [Bmim]Br. This domino reaction involved the in situ generation of 1,3-dienes from acid-mediated dehydration of various pinacoles and the sequential Diels–Alder reaction.

A highly efficient Cu-catalyzed 1,4-difunctionalization of isoquinolinium salts was developed with ether and X– (X = Br, Cl) as the halogen source under mild conditions. This transformation involves the combination of oxidative coupling and copper-catalyzed halogen atom-transfer radical processes. This method not only provides an efficient way to prepare various substituted azaarenes but also achieves the selective construction of C(sp2)–X (X = Br, Cl) bonds from a halogen anion and nucleophilic carbon atom via a free-radical process.

The base-promoted cycloaddition reaction of N-cyanomethylisoquinolinium chloride with 2-arylidene-1,3-indanediones in dry tetrahydrofuran resulted in the expected spiro[indene-2,1′-pyrrolo[2,1-a]isoquinoline] derivatives. However, the triethylamine-promoted three-component reaction of N-cyanomethylisoquinolinium chloride, aromatic aldehydes, and two molecules of 1,3-indanediones in acetonitrile afforded unique spiro[benzo[f]imidazo[5,1,2-cd]indolizine-4,2′-indene] derivatives in satisfactory yields through tandem double [3 + 2] cycloaddition reactions.

Three-component reactions of triphenylphosphine, but-2-ynedioate, and isatylidene malononitrile (ethyl cyanoacetate) in dimethoxyethane resulted in triphenylphosphanylidene spiro[cyclopentane-1,3′-indolines] in satisfactory yields. Furthermore, similar three-component reactions of triphenylphosphine, hex-2-en-4-ynedioate, and isatylidene malononitrile (ethyl cyanoacetate) afforded functionalized spiro[cyclopent[2]ene-1,3′-indolines] in good yields.

The functionalized spiro[indoline-3,2'-pyridine]-3',4',5',6'-tetracarboxylates were efficiently synthesized by BF3·OEt2-catalyzed reactions of isatin-3-imines with acetylenedicarboxylates in methylene dichloride. Under similar conditions, the BF3·OEt2-catalyzed three-component reactions of acetylenedicarboxylates, arylamines, and isatins afforded functionalized spiro[indoline-3,4'-pyridine]-2',3',5',6'-tetracarboxylates in moderate yields.

A simple protocol for the construction of novel dispirocyclopentanebisoxindoles is accomplished by the base promoted domino reactions between two molecules of 3-phenacylideneoxindoles with the participation of solvents, alcohol, or other added nucleophiles such as amines or thiophenols. Significantly, this domino reaction results in the complex dispiro compounds with high yields and diastereoselectivity, which would allow construction of dispirocyclopentanebisoxindole with four and five diastereoisomeric centers using simple materials.

Microporous polycarbazole via straightforward carbazole-based oxidative coupling polymerization is reported. The synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation. The Brunauer-Emmett-Teller specific surface area for obtained polymer is up to 2220 m(2) g(-1). Gas (H(2) and CO(2)) adsorption isotherms show that its hydrogen storage can reach to 2.80 wt % (1.0 bar and 77 K) and the uptake capacity for carbon dioxide is up to 21.2 wt % (1.0 bar and 273 K), which show a promising potential for clean energy application and environmental field. Furthermore, the high selectivity toward CO(2) over N(2) and CH(4) makes the obtained polymer possess potential application in gas separation.

Hexaphenylbenzene-based porous organic polymers are prepared smoothly through palladium-catalyzed C–C coupling polymerization. According to the obtained nitrogen physisorption isotherms, the Brunauer–Emmett–Teller specific surface area for these polymers varies between 742 and 1148 m2 g–1. Gravimetric hydrogen adsorption isotherms show that the adsorption capacity for hydrogen is up to 1.5 wt % at 1.13 bar and 77 K. Thanks to the propeller-like structure, unique electronic feature, and efficient preparation, hexaphenylbenzene can be taken as a promising building block for designing porous polymers with special properties.

A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the structure of cyclic 1,3-diketone. The key steps are proposed to involve Michael addition of the enamino ester formed in situ from the reaction of arylamine with dimethyl acetylenedicarboxylate to arylidine cyclic 1,3-diketones.

A practical and efficient procedure for the preparation of the polysubstituted dihydropyridines was developed through a unique four-component reaction of aromatic aldehydes, malononitrile, arylamines, and acetylenedicarboxylate in ethanol in the presence of triethylamine as a base promoter. This four-component reaction is atom-efficient, high-yielding, and applicable to a wide variety of four-component reactions.

A facile template method was described for the decoration of organic microtubes with various nanoparticles (NPs), which was achieved in a straightforward "mix" process in the presence of templates and resorcinarene-functionalized nanoparticles (AuNPs, AgNPs, PtNPs, and PdNPs). A combination of UV-visible spectra and Fourier transform-infrared spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction measurements, contact angle experiment, and energy dispersive X-ray spectroscopy was used for analysis. Interestingly, it was found that NPs could be encapsulated into the microtubes during the process of resorcinarene self-assembly. As a model system, AuNP-loaded microtubes were investigated and discussed, and loaded nanoparticles with a narrow size distribution were observed. Furthermore, AuNP-decorated microsheets could also be obtained by the assembly of resorcinarene with hydrazide groups. Remarkably, it was also observed that the incorporated NPs could be redispersed by treating the NP-loaded microtubes, which made it possible to realize the uptake and release of given nanoparticles. This procedure was scalable to diverse resorcinarene-based self-assemblies and applicable to various metal nanoparticles that decorate by resorcinarenes.

An efficient synthetic procedure for the preparation of fused 2,3-dihydrofuran derivatives was developed with the assistance of pyridinium ylide. A sequential one-pot, two-step tandem reaction starting from pyridine, aromatic aldehyde, dimedone, or 4-hydroxycoumarin and alpha-phenacyl bromide or p-nitrobenzyl bromide with triethylamine as catalyst proceeded smoothly in acetonitrile. (1)H NMR spectroscopy and single-crystal analysis demonstrated that the obtained 2,3-dihydrofurans are trans isomers.

A sequential one-pot two-step tandem reaction for efficient synthesis of polysubstituted cyclopropanes has been developed. The three-component reaction of alpha-halogenated methylene compounds, aromatic aldehydes, and acetonitrile derivatives produced first the intermediates pyridinium salts and electron-deficient olefins, followed by cyclopropanation of pyridinium ylide with electron-deficient olefins in situ to afford polysubstituted cyclopropanes. Target compounds were obtained in high yields and were diastereomerically pure after recrystallization.

Polysubstituted pyrido[1,2-a]benzimidazole derivatives are efficiently produced in moderate yields in a novel one-pot, four-component reaction from pyridine or 3-picoline, chloroacetonitrile, malononitrile, and aromatic aldehyde in refluxing acetonitrile. The mechanism of this novel reaction was believed involving the formation of polysubstituted benzenes with subsequent substitution and annulation reaction of pyridine. All pyrido[1,2-a]benzimidazoles, polysubstituted benzenes, polysubstituted indoles, and some key reaction intermediates are characterized by (1)H and (13)C NMR, MS, IR spectra, and elemental analysis as well as X-ray crystallography.

A series of lithium salts of the anions [(μ-RTe)(μ-CO)Fe2(CO)6-] (R = n-Bu, Ph, o-MeC6H4, p-MeC6H4) were prepared by reaction of organolithium reagents with elemental tellurium, followed by treatment of the intermediates RTeLi with Fe3(CO)12 in THF at room temperature. Further treatment of the lithium salt [(μ-RTe)(μ-CO)Fe2(CO)6-]Li+ (R = n-Bu) in situ with PhC⋮CH at room temperature yielded Fe2Te2 and Fe2Te clusters (μ-n-BuTe)2Fe2(CO)6 (1) and (μ-n-BuTe)(μ-σ,π-PhCCH2)Fe2(CO)6 (2), whereas the lithium salts [(μ-RTe)(μ-CO)Fe2(CO)6-]Li+ (R = n-Bu, Ph, o-MeC6H4, p-MeC6H4) were treated in situ with acid chlorides, such as MeC(O)Cl and p-MeC6H4SO2Cl, to afford Fe2Te2 clusters (μ-RTe)2Fe2(CO)6 (R = n-Bu (1), Ph (4), o-MeC6H4 (6), p-MeC6H4 (8) and double Fe2Te2 clusters [(μ-RTe)Fe2(CO)6]2(μ-Te−Te-μ) (R = n-Bu (3), Ph (5), o-MeC6H4 (7), p-MeC6H4 (9)). In addition, the new single clusters, except 1, were separated into ae and ee (where a = axial and e = equatorial) isomers and characterized individually, whereas t...

The dithioformato-bridged anionic salts [Et3NH][(μ-RE)(μ-SCS)Fe2(CO)6], generated from CO-bridged anionic complexes [Et3NH][μ-RE)(μ-CO)Fe2(CO)6] and carbon disulfide, reacted in situ with SO2Cl2 in THF to afford a series of novel dithioformato-bridged double clusters [(μ-RE)Fe2(CO)6]2(μ-SCS-μ) (3a−e) (3a, RE = EtS; 3b, n-PrS; 3c, t-BuS; 3d, PhSe; 3e, p-MeC6H4Se). A single-crystal diffraction analysis of 3c was undertaken and has confirmed the proposed structure.

The CO-bridged anions [(μ-RE)(μ-CO)Fe2(CO)6]- reacted with S8 to form the sulfur-centered anions (μ-RE)(μ-S-)Fe2(CO)6 (4; E = S, Se), whereas reaction of the anions with Se8 yielded the selenium-centered anions (μ-RE)(μ-Se-)Fe2(CO)6 (6; E = S, Se). Interestingly, reaction of 4 with SO2Cl2 afforded the S−S-bonded clusters [(μ-RE)Fe2(CO)6]2(μ-S−S) (5), whereas reaction of 6 with SO2Cl2 produced the μ4-Se clusters [(μ-RE)Fe2(CO)6]2(μ4-Se) (8); clusters 8 could also be produced by the action of anions 6 on succinoyl chloride or p-phthaloyl chloride, while the μ4-S clusters [(μ-RE)Fe2(CO)6]2(μ4-S) (9) were generated by reaction of anions 4 with the above organic bis acid chlorides under similar conditions. Also, reaction of 4 (E = S) with p-MeC6H4SO2Cl gave the μ4-S clusters [(μ-RE)Fe2(CO)6]2(μ4-S) (9; E = S) and the expected Fe2S2 butterfly clusters (μ-RE)(μ-p-MeC6H4SO2S)Fe2(CO)6 (10), whereas anion 6 reacted with p-MeC6H4SO2Cl to afford the unexpected SO-bridged complexes (μ-RE)(μ-p-MeC6H4SO2)Fe2(CO)6 (11) a...