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A novel and highly efficient Pd-catalyzed arylation of sulfenate anions with aryl thianthrenium salts is demonstrated. This procedure provides a practical protocol to synthesize various diaryl and alkyl aryl sulfoxides in moderate-to-good yields. The new approach shows mild reaction conditions, broad substrate scope, and good functional group tolerance.

A convenient synthetic protocol for diverse fused chromenes was successfully developed by a three-component reaction of alkyl isocyanides, dialkyl but-2-ynedioates, and various cyclic 1,3-dipolarophiles containing o-hydroxyphenyl group. In the absence of any catalyst, the three-component reaction of alkyl isocyanides, dialkyl but-2-ynedioates, and 3-(o-hydroxyarylidene)indolin-2-ones in tetrahydrofuran at 60 °C resulted in unique functionalized spiro[cyclobuta[c]chromene-1,3′-indolines] in good yields and with high diastereoselectivity. However, the similar three-component reaction with 2-(5-halo-2-hydroxyarylidene)indolin-2-ones afforded unexpected chain products in satisfactory yields. In addition, the three-component reaction of alkyl isocyanides, dialkyl but-2-ynedioates, and 2-(o-hydroxyarylidene)-1,3-indanediones in tetrahydrofuran at 60 °C resulted in complex indeno[2′,1′:5,6]pyrano[3,4-c]chromene derivatives in high yields and with high diastereoselectivity.

We have developed an efficient protocol for the synthesis of spiro[indoline-pyridine]dicarboxylates and substituted alkylidene oxindoles through [3 + 3] cycloaddition and Michael addition individually by azomethine ylides and various MBH carbonates of isatins. The selective generation of cyclic products and chain products was achieved by changing the substituents at the 3-position of the oxindoles. The features of this method include convenient catalysts, mild reaction conditions, and broad substrate scopes.

A highly efficient palladium-catalyzed asymmetric tandem aza-Heck/Sonogashira coupling reaction of O-phenyl hydroxamic ethers with terminal alkynes is described. This protocol enables versatile access to challenging chiral isoindolinone derivatives bearing a quaternary stereogenic center. The palladium-catalyzed aminoalkynylation reaction shows broad functional group tolerance and allows the straightforward preparation of isoindolinones with high efficiency and excellent enantioselectivity under mild conditions. DFT calculations were performed to disclose the reaction mechanism and the origins of the enantioselectivity.

Abstract: A one-pot multi-component reaction is developed for the efficient synthesis of 4,5-dibenzylidene octahydroacridines in high yields. The reaction is performed by the tandem reaction of three molar equivalent aromatic aldehydes with two molar equivalent 4-alkylcyclohexanone in the system of NH4OAc/HOAc under microwave irradiation. MediaObjects/11532_2008_27_Fig1_HTML.jpg

The domino reactions of 1,3-thiazolidinedione, malononitrile, and aromatic aldehydes in the presence of different organic amines were studied. Secondary amines such as pyrrolidine, piperidine, morpholine, and dimethylamine and primary amines such as benzylamine yield dihydrothiophene derivatives through a domino ring-opening/recyclization reaction of 1,3-thiazolidinedione. Bulky diethylamine, diisopropylamine, and 1,4-diazabicyclo[2.2.2]octane give spirocyclohexano-1,3-thiazole through a double Michael addition/spirocyclization reaction.

Oxazines are an important class of compounds in oxazine ligands and medical chemistry. Here, we describe a linear-selective allylation of imines with allyl electrophiles via cross-electrophile coupling reactions, followed by cyclization with halogenated reagents, providing a new strategy to afford oxazine compounds with a tetrasubstituted carbon center. Mechanistic studies indicate that α-amino carbanion, generated by successive single-electron transfer processes, is a key intermediate for nucleophile attack on π-allylpalladium in photoredox/palladium catalysis.

The domino reaction of alkyl and aryl isocyanides with two molecules of 2-arylidene-1,3-indanediones in acetonitrile at 80 °C resulted in unique functionalized spiro[dibenzo[a,f]azulene-6,2′-indenes] in good yields, in which the two 2-arylidene-1,3-indanediones acted as different building blocks to construct the polycyclic system. More importantly, the unprecedented anticipation of the ortho-position of benzylidene group to form a novel dibenzo[a,f]azulene ring through a formal [5 + 2] cycloaddition process was first observed. On the other hand, DABCO-promoted reaction of the isocyanides with two molecules of 2-arylidene-1,3-indanediones in acetonitrile at 80 °C afforded functionalized spiro[cyclopenta[a]-indene-2,2′-indene] derivatives.

Platinum(II)-based metallacycles/cages have obtained tremendous attention due to their fascinating topology and wide range of applications, such as fluorescent materials, cell imaging, and tumor treatment. In this work, a metallatetragon (1) was constructed from 4-(4-(1,2,2-triphenylvinyl)phenyl)pyridine (2) and 90° cis-Pt(II) (Pt) in acetone through the strategy called “coordination driven self-assembly”. Interestingly, through co-assembly of 1and poly(ethylene glycol)-modified tetraphenylethylene (TPE-PEG22), fluorescent nanotheranostics, which could generate singlet oxygen (1O2) under the NIR irradiation and release Pt drugs under a low-pH microenvironment, were prepared successfully. The obtained theranostics could realize living cell imaging and synergistic chemo-photodynamic therapy in vitroand in vivo.

Diverse functionalized dihydrobenzofuran spiro-indanedione-oxindole scaffolds were conveniently synthesized by base-promoted cyclization reaction of Morita–Baylis–Hillman (MBH) carbonates of isatins and 2-(o-hydroxybenzylidene)-1,3-indanediones. The two diastereomeric dispiro[indene-2,1′-cyclopenta[b]benzofuran-2′,3″’-indolines] could be selectively synthesized by using DABCO or DMAP as a base promoter. More importantly, DABCO or DMAP facilitated the annulation reaction of MBH formates of isatins and 2-(o-hydroxybenzylidene)-1,3-indanediones selectively, resulting in spiro[cyclopropa[c]chromene-1,2′-indene]-1′,3′-diones or dispiro[indene-2,1′-cyclopenta[b]benzofuran-2′,3″’-indolines]. Additionally, a similar reaction with MBH maleimides of isatins afforded dispiro[indene-2,5′-benzofuro[2′,3′:1,5]cyclopenta[1,2-c]pyrrole-4′,3″’-indolines] in high yields and with high diastereoselectivity.

A highly efficient Pd-catalyzed carboetherification reaction of β,γ-unsaturated ketoximes with propargylic acetates is demonstrated. This method provides a practical protocol for accessing the incorporation of an allene moiety into 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines. The salient features of this transformation include a broad substrate scope, good functional group tolerance, an easy scale-up, versatile transformations, and applications in the late-stage modification of drugs.

Metal nanoparticle catalysts have attracted great interest because they possess high surface-to-volume ratios and exhibit a very large number of catalytically active sites per unit area. However, high surface-to-volume ratios will induce nanoparticle aggregates during the catalytic reactions, making them lose their catalytic activity. In this work, a monoterpyridine-unit-functionalized pillar[5]arene (TP5) was synthesized successfully, which can be used as anchoring sites for the controllable preparation of well-dispersed palladium nanoparticles [TP5/Pd(0) NPs]. The as-prepared TP5/Pd(0) NPs were fully characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, and powder X-ray diffraction. Importantly, the ultrafine TP5/Pd(0) NPs are found to be excellent and reusable catalysts for the reduction of nitrophenols in aqueous solution.

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 ortho-hydroxychalcones or ortho-hydroxy-β-nitrostyrenes. The complex polycyclic compounds were conveniently synthesized in satisfactory yields and with high diastereoselectivity. This protocol provides a swift and convenient approach for the assembly of diverse highly functionalized dihydrobenzofuran spirooxindoles and also features broad substrate scope, high molecular convergence, and excellent atomic economy.

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.

The concentrated hydrochloride catalyzed reaction of 3‐(indol‐3‐yl)maleimides with (E)‐4‐arylidene‐5‐methyl‐2‐phenylpyrazol‐3‐ones in acetonitrile at room temperature afforded unexpected Michael addition product in high yields, which could be easily converted to the cis/trans‐diastereoisomers of spiro[pyrazole‐4,5′‐pyrrolo[3,4‐c]carbazoles] with the nearly 2 : 1 ratios by further oxidation with DDQ. On the other hand, the similar one‐pot two‐step reaction of 3‐(indol‐3‐yl)maleimides with (E)‐5‐arylidene‐2‐phenylthiazol‐4‐one predominately gave cis‐diastereoisomers of spiro[pyrrolo[3,4‐c]carbazole‐5,5′‐thiazoles] in satisfactory yields. The reaction mechanism included domino acid catalyzed Michael addition and DDQ oxidative coupling process The spirooxindoles were efficiently synthesizedby domino acid catalyzed Michael addition and DDQ oxidative coupling process.

The DABCO promoted domino reaction of 1‐(2‐hydroxyphenyl)‐3‐phenylprop‐2‐en‐1‐ones and alkyl propiolate or dialkyl but‐2‐ynedioate in toluene at high temperature resulted in methyl 3‐(2‐hydroxybenzoyl)‐1‐naphthoates or dimethyl 3‐(2‐hydroxybenzoyl)naphthalene‐1,2‐dicarboxylate in moderate to good yields. The hydroxyl group played a crucial rule in the reaction. The reaction mechanism of this formal [4+2] cycloaddition reaction was believed with initially formation of methyl 3‐(2‐cinnamoylphenoxy)acrylate, intramolecular Diels‐Alder reaction, ring‐opening of benzo[b]xanthene and aromatization process. The DABCO‐promotedintramolecular Diels‐Alder reaction afforded functionalized naphthalenes in good 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 CuSO4promoted 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, CuSO4promoted 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.

p-TsOH catalyzed Diels-Alder reaction of 3-(indol-3-yl)maleimides with 3-phenacylideneoxindoles in toluene afforded cis/transisomers of 3a',4′,6′,10c'-tetrahydrospiro[indoline-3,5′-pyrrolo[3,4-c]carbazoles] in nearly comparable yields, which could be easily converted to the corresponding 4′,6′-dihydrospiro[indoline-3,5′-pyrrolo[3,4-c]carbazoles] in high yields and with high diastereoselectivity by further DDQ oxidation.

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/transisomeric 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.

Spiro[indoline‐3,7′‐pyrrolo[1,2‐a]azepines] were conveniently synthesized in satisfactory yields and with high diastereoselectivity from three‐component reaction of L‐proline, isatins and chalcones and sequential reaction with dimethyl but‐2‐ynedioate or methyl propiolate in refluxing methanol. The ferrocenyl‐chalcones and dibenzylideneacetones were also successfully used in this one‐pot two‐step reaction to give novel ferrocenyl and styryl‐substituted spiro compounds. The reaction mechanism included domino [3+2] cycloadddtition reaction of azomethine ylide with chalcone and ring‐expansion reaction of in situgenerated spiro[indoline‐3,3′‐pyrrolizine] with electron‐deficient alkynes. Synthetic methods: Spiro[indoline‐3,7′‐pyrrolo[1,2‐a]azepines] were conveniently synthesized from domino [3+2] cycloadddtition reaction of azomethine ylide with chalcone and ring‐expansion reaction of in situ generated spiro[indoline‐3,3′‐pyrrolizine].

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 afforded spiro[indeno[1,2-b]phenothiazine-6,3′-indolines] or spiro[cyclopenta[b]phenothiazine-4,3′-indolines] in good yields and with high diastereoselectivity. More interestingly, a similar three-component reaction with 4-hydroxychromen-2-one resulted in the unexpected polycyclic spiro[benzo[b]chromeno[3′,4′:5,6]pyrano[2,3-e][1,4]thiazine-7,3′-indolines] in satisfactory yields. A plausible reaction mechanism was rationally proposed for formation of different kinds of the spiro compounds, and the stereochemistries of the various spiro compounds were clearly elucidated.

The 1,3-dipolar cycloaddition reaction of dimethyl hex-2-en-4-ynedioate with in situgenerated azomethine ylides derived from reaction of l-proline and isatins in methanol resulted in functionalized tetrahydrospiro[indoline-3,3′-pyrrolizine]-acrylates as main products and hexahydrospiro[indoline-3,3′-pyrrolizine]propiolates as minor products.

The trans-1,3-disubstituted or cis/trans-1,2-disubstituted 7,9-diazaspiro[4.5]dec-1-enes were selectively synthesized in high yield from triphenylphosphine promoted annulation reaction.

The series of salen-bridged bis-pillar[1]arenes were conveniently prepared by condensation reaction of 5,5′-methylenebis(2-hydroxybenzaldehyde) or 5,5′-(propane-2,2-diyl)bis(2-hydroxybenzaldehyde) with mono-amido-functionalized pillar[5]arenes. The 1H NMR and 2D-NOESY spectra as well as single crystal structure clearly indicated that the salen-bridged bis-pillar[5]arenes with longer alkylene linker (m = 0, 1, 3) formed the fascinating bis-[1]rotaxanes, while those with short hydrazine and ethylenediamino linker predominately existed in free form.

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.

We have developed a convenient synthetic protocol for efficient construction of significant dihydrobenzofuran and benzofuran scaffolds by Lewis base-mediated annulation reaction ortho-iminophenols and ortho-vinylphenols with MBH carbonates of isatins under mild and metal-free conditions. The selective generation of different kinds of dihydrobenzofuran and benzofuran derivatives was successfully achieved by employing different substituted isatin-derived MBH carbonates with ortho-N-tosyliminophenols and ortho-vinylphenols. The features included broad substrate scopes, excellent functional group compatibility, high molecular diversity, and atomic economy.

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 m2g–1. Gas (H2and CO2) 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 CO2over N2and CH4makes the obtained polymer possess potential application in gas separation.