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A series of polysubstituted indol-3-yl substituted pyran derivatives have been synthesized via one-pot multicomponent reactions of aldehydes, malononitrile with 3-cyanoacetyl indoles under ultrasonic irradiation. This method has the advantages of high yield, easy operation, short-reaction time, mild-reaction condition, and catalyst recyclability.

Cobalt catalysis: Synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles was achieved by using cobalt(II) acetate catalyzed isocyanide insertion to o-diaminobenzene, 2-aminobenzenethiol, and 2-aminophenol derivatives in 1,4-dioxane (see scheme). It was found that the reaction proceeded efficiently to give the desired products in up to 95 % isolated yields by C-N and C-S (O, N) formation in a single step.

The reaction of anilines with cyclic tert-enamides affords 2,4-dibsubstituted tetrahydroquinoline units with complete cis diastereoselectivity.

A facile and efficient copper-catalyzed method for the synthesis of 4H-3,1-benzoxazin-4-one derivatives has been developed. This procedure is based on a tandem intramolecular C–N coupling/rearrangement process. This method would provide a new and useful strategy for construction of N-heterocycles.

The simple and efficient method allows the preparation of a wide range of alkynones via alkynyl imines [cf.

A novel catalyst-free one-pot tandem reaction for the stereoselective construction of polycyclic spiroindolines was developed. This method offers a straightforward access to structurally diverse polycyclic spiroindoline derivatives in high yields (up to 90%) with excellent levels of diastereoselectivity.

An efficient TFA-catalyzed cleavage of C–N bonds in alkylation of indoles by tertiary enamides was described. A variety of bisindolylalkane derivatives, especially 3,3-bisindolylpropanoates, were expeditiously synthesized in good yields.

Various pyrrole derivatives are synthesized by a new three-component reaction from easily available starting materials.

1-Pentyl-3-methylimidazolium hydrogen sulfate and several structurally related ionic liquids are synthesized and applied as catalyst for the benzylation of nitrogen, sulfur, and carbon nucleophiles.

A novel CuI/BF3·Et2O/O2-mediated reaction utilizing ketones and benzylamines for the construction of substituted imidazoles in one step under mild conditions has been demonstrated. This protocol involved the removal of eight hydrogen atoms, the functionalization of four C(sp3)–H bonds and three new C–N bond formations.

This is a simple and efficient method for the synthesis of isocoumarins and phthalides from easily accessible substrates in good yields.

A novel silicon-based compound, 10-phenyl-2'-(triphenylsilyl)-10H-spiro[acridine-9,9'-fluorene] (SSTF), with spiro structure has been designed, synthesized, and characterized. Its thermal, electronic absorption, and photoluminescence properties were studied. Its energy levels make it suitable as a host material or exciton-blocking material in blue phosphorescent organic light-emitting diodes (PhOLEDs). Accordingly, blue-emitting devices with iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C(2)']picolinate (FIrpic) as phosphorescent dopant have been fabricated and show high efficiency with low roll-off. In particular, 44.0 cd A(-1) (41.3 lm W(-1)) at 100 cd m(-2) and 41.9 cd A(-1) (32.9 lm W(-1)) at 1000 cd m(-2) were achieved when SSTF was used as host material; 28.1 lm W(-1) at 100 cd m(-2) and 20.6 lm W(-1) at 1000 cd m(-2) were achieved when SSTF was used as exciton-blocking layer. All of the results are superior to those of the reference devices and show the potential applicability and versatility of SSTF in blue PhOLEDs.

The two-step reaction sequence from (VI) via (VIII) to (IX) can also be conducted as a one-pot process with similar overall yields.

A simple and efficient palladium-catalyzed carbonylative Sonogashira coupling via tert-butyl isocyanide insertion has been developed, which demonstrates the utility of isocyanides in intermolecular C-C bond construction. This methodology provides a novel pathway for the synthesis of alkynyl imines which can undergo simple silica gel catalyzed hydrolysis to afford alkynones. The approach is tolerant of a wide range of substrates and applicable to library synthesis.

Optimized conditions are developed for the cross-coupling with symmetrical and unsymmetrical 1,3-dicarbonyl compounds.

Indium trichloride was successfully applied to allylation reaction of aldehydes using allytributyltin in ionic liquids. This accelerated catalytic system afforded the allylated products of various aldehydes in moderate tohigh yields. Preliminary studies on the enantioselectivity of this type of reaction have resulted in low to moderate enantioselectivities.

Mukaiyama aldol reactions using ketene silyl acetals with various aldehydes proceed smoothly in ionic liquids to afford the corresponding aldol products in moderate yields.

Oxidation of α-iodo ketone in CH 2 Cl 2 using m-chloroperbenzoic acid yields α,β-unsaturated ketone by β-H elimination in good yield. This reaction affords a new and convenient synthetic method for α,β-unsaturated ketone from u-iodo ketone.

The insertion of diaroylmethanes into the dione part of (I) proceeds under transition metal free conditions.

Cobalt catalysis: Synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles was achieved by using cobalt(II) acetate catalyzed isocyanide insertion to o-diaminobenzene, 2-aminobenzenethiol, and 2-aminophenol derivatives in 1,4-dioxane (see scheme). It was found that the reaction proceeded efficiently to give the desired products in up to 95 % isolated yields by C-N and C-S (O, N) formation in a single step.

Reaction of alkenes [cyclohexene (1), cycloheptene (2), cyclooctene (3), 1-heptene (4), 1-octene (5), styrene (6), 1,7-octadiene (7), indene (8), and 1,2-dihydronaphthalene (9)] with cerium(IV) sulfate (CS) in carboxylic acids [formic acid, acetic acid, and propionic acid] readily yielded the corresponding carboxylic esters. This addition reaction follows the Markovnikov rule. This reaction provides a new simple method for preparing carboxylic esters from alkenes. It was also found that this method is useful for formylation.

Efficient electrophilic substitution reactions of indoles with various aldehydes proceed smoothly in ionic liquids using Lewis acids, In(OTf) 3 , YbCl 3 , InCl 3 , BiCl 3 , and ZnCl 2 , to afford the corresponding bis(indolyl)methanes in high yields.

Ceric ammonium nitrate efficiently catalyzes the Michael addition of indole to α,β-unsaturated carbonyl ketones by means of alkylation of indole under ultrasonic irradiation to afford the corresponding adduct in excellentyields. The substitution on the indole nucleus occurred exclusively at the 3-position, and N-alkylation products have not been observed.

Indole undergoes conjugate addition with α,β-unsaturated ketones by means of alkylation of indole in the presence of a catalytic amount of molecular I 2 at room temperature to afford the corresponding adduct in excellent yields (up to 96%). The substitution on the indole nucleus occurred exclusively at the 3-position. N-alkylation products have not been observed.

A novel and highly efficient strategy for the synthesis of isocoumarins and phthalides through a palladium(0)-catalyzed reaction incorporating tert-butyl isocyanide has been developed. This process, providing one of the simplest methods for the synthesis of this class of valuable lactones, involves two steps including cyclization reaction and simple acid hydrolysis. The methodology is tolerant of a wide range of substrates and applicable to library synthesis.

Multicomponent reactions of acenaphthylene-1,2-dione with diaroylmethanes and electron-rich pyrazol-5-amines have been discovered. A series of new and polyfunctionalized pentacyclic pyrazole-fused naphtho[1,8-fg]isoquinolines were regioselectively synthesized. The reactions were easy to perform simply by mixing three common reactants in AcOH. During these reaction processes, the insertion of active methylene of diaroylmethane into the sp(2)-sp(2) C-C bond of the cyclohexa-2,5-dienone ring was readily achieved and two C-C bonds were cleaved under transition-metal-free conditions.

Treatment of various indoles with enamide (II) or (IX) provides pharmaceutically interesting derivatives.

Double Michael addition reaction of divinyl ketones (II) and (IV) with N-unprotected oxindoles (I) and N-phenyl pyrazolones (VI) is efficiently catalyzed by an N-Boc-D-phenylglycine—epiquinine-derived amine organocatalyst system.

A novel and efficient approach to the title pyrazolopyridine derivatives such as (IV), (VI), (VIII) is developed using a one-pot, three-component reaction involving acenaphthylenedione (II) and aminopyrazoles (III).

α-Functionalization of ferrocenyl alcohols with various C-, N-, O- and S-nucleophiles proceeds smoothly at room temperature in acetic acid.

1,3-Dipolar cycloadditions involving 1,4-naphthoquinone and an azomethine ylide generated from α-amino acids and isatins have been used in this reaction to afford the pyrrolidine-2-spiro-3′-oxindole 4 or 5 with moderate to excellent yields.

New crown ether carrying two fluorionophores of cis-dibenzothiazolyldibenzo-24-crown-8 was synthesized from cis-diformyldibenzo-24-crown-8 and 2-aminobenzenethiol. The binding behavior and the optical properties of the crown ether were examined through UV-visible spectroscopy and fluorescence spectroscopy. When complexed with Na+, K+, Rb+, and Cs+ ions, it led to intramolecular charge transfer and caused the changes of the fluorescence spectra. The protonation of the crown ether was also studied. With protonation using CF3COOH, the absorption bands and the fluorescence spectroscopy changed, the maximal fluorescence wavelengths red shifted and the fluorescence intensity with the maximum at 433 nm enhanced strongly. J. Heterocyclic Chem., (2011).

Nucleophilic substitution of ferrocenyl alcohols with various aliphatic alcohols in the presence of a catalytic amount of ytterbium triflate [Yb(OTf)3] was studied. It was found the unsymmetrical ferrocenyl ethers could be easily obtained in excellent yields when the reactions were performed in primary and secondary alcohols. However, in other organic non-alcoholic solvents such as acetonitrile, the formation of symmetrical ferrocenyl ethers rather than unsymmetrical ones was observed.

The synthesis of a variety of title furoindole derivatives, e.g. (V) and (VIII), is presented, involving a three-component coupling of 1,3-diketones with o-halobenzaldehydes and isocyanides, followed by intramolecular Cu-catalyzed Ullmann reaction.

The reaction which is conducted under-solvent free conditions leads to Markovnikov addition products.

In the absence of a solvent and a catalyst, β-arylamino ketones are obtained in most cases as neat products without the need of column chromatography.

Reactions of isocyanides with 2-mercaptobenzothiazole and 2-mercaptobenzoxazole afforded a series of compounds containing formamidine framework in moderate to high yields. These organic transformations were performed under mild and catalyst-free conditions. In addition to promoting the reactions, the use of ultrasound irradiation also allowed the process to be carried out under air atmosphere. A possible reaction mechanism was proposed based on the experimental results.

The microwave-assisted Michael addition of diethyl malonate (II) to ferrocenyl-substituted chalcones (I) under solvent-free conditions is described.

Thiourea-modified cinchona alkaloids as bifunctional catalysts and a base could catalyze a stepwise [5+1] cyclization of divinyl ketones with nitromethane via double Michael additions, furnishing optically active 4-nitro-cyclohexanones with good yields, excellent diastereoselectivities (>20 ∶ 1) and high enantiomeric ratios (up to 97 ∶ 3).

Thiourea-modified cinchona alkaloids as bifunctional catalysts and a base could catalyze a stepwise [5+1] cyclization of divinyl ketones with nitromethane via double Michael additions, furnishing optically active 4-nitro-cyclohexanones with good yields, excellent diastereoselectivities (>20 ∶ 1) and high enantiomeric ratios (up to 97 ∶ 3).

Friedel—Crafts reactions catalyzed by ferric nitrate in water at room temperature between various indoles and tertiary enamides are described.

Ferrocenyl alcohols undergo nucleophilic substitution reactions to give the arylamine, thioether, and ether products (III), (V), and (VII) in moderate to good yields.

A convenient and highly efficient multicomponent protocol has been developed for the synthesis of various poly-substituted 2-(pyridin-2-yl)imidazoles from 2-cyanopyridine, corresponding aromatic aldehydes, and NH(4)OAc/primary amine. Notably, tri-substituted 2-(pyridin-2-yl)imidazoles were highly yielded when aromatic primary amines were used as substrates, but both di- and tri-substituted 2-(pyridin-2-yl)imidazoles were obtained in one pot when some aliphatic primary amines were used as substrates.