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A one-pot four-component synthesis of 6-aryl-6H-dibenzo[e,i][1,3,7,2]oxadiazaborecin-8(7H)-ones is described. Heating a mixture of isatoic anhydride and a benzylamine afforded the corresponding anthranilamide derivative, which was condensed with a 2-hydroxybenzaldehyde and an arylboronic acid under solvent-free conditions to produce bridgehead bicyclo[4.4.0]-boron heterocycles in good to excellent yields. Single-crystal X-ray analysis conclusively confirms the structures of the obtained bridgehead bicyclic 6–6 heterocyclic compounds.

An efficient three-component synthesis of benzimidazo[1,2-a]quinoline-6-carbonitriles is described. Condensation reaction of a benzene-1,2-diamine and a cyclohexane-1,3-dione gave an enamine intermediate, which on treatment with an arylidenemalononitrile in water–ethanol (1:1) afforded the title compounds in good to excellent yields.

A transition metal-free cross-dehydrogenative coupling reaction is described for the preparation of 3-acylcoumarins. Heating a mixture of a coumarin, an aldehyde, and the K 2 S 2 O 8 /Aliquat 336 system in chlorobenzene at 100 °C for 8 h regioselectively afforded the corresponding 3-acylcoumarin derivatives in good to excellent yields.

Whereas aromatic aldehydes bearing electron-donating substituents afford the corresponding anhydrides in good yields, derivatives with electron-withdrawing substituents, e.g. (Ig,h), fail to give the transformation.

A novel, one-pot, multicomponent synthesis of 5′-amino-2,2′-dioxospiro[indoline-3,3′-pyrrole]-4′-carbonitriles is described. The Knoevenagel condensation reaction between isatin derivatives and malononitrile gave the corresponding cyclic arylmethylidenemalononitriles that, on treatment with isocyanides, afforded 2,2′-dioxospiro-bis-γ-lactams in good to excellent yields.

An efficient and mild three-component synthesis of isoindolin-1-one-3-phosphonates is described. The reaction between a 2-formylbenzoic acid, a primary amine, and a trialkyl phosphite proceeded at ambient temperature under catalyst- and solvent-free conditions to afford the desired compounds in excellent yields.

An efficient synthesis of 2,4,6-triarylpyridines is described. Heating a mixture of an acetophenone, a benzyl halide, and ammonium acetate under neat conditions afforded the corresponding Krohnke pyridines in excellent yields.

A one-pot four-component synthesis of thieno[2,3-d]pyrimidin-4-amines via sequential Gewald/cyclocondensation reactions is described. 2-Aminothiophene-3-carbonitriles obtained from the Gewald reaction between cyclic ketones, malononitrile, and sulfur underwent a condensationcyclization reaction with benzonitriles under solvent-free conditions to afford the title compounds in excellent yields.

A one-pot and three-component reaction is described for the preparation of 2,3-disubstituted isoindolin-1-ones. Heating a mixture of 2-formylbenzoic acid, a cyclic six-membered β-dicarbonyl compound, and a benzylamine under solvent-free conditions afforded the title compounds in good to excellent yields. The generality of the reaction was shown by the use of various β-dicarbonyl compounds including 1,3-cyclohexadione, dimedone, Meldrum’s acid, N,N-dimethylbarbituric acid, and some benzylamine derivatives.

A novel oxidation–aromatization of alkyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylates is reported. The Gewald product, obtained from three-component condensation reaction between a cyclohexanone, an alkyl cyanoacetate, and sulfur, underwent an oxidation reaction in dimethyl sulfoxide in the presence of a catalytic amount of p-toluenesulfonic acid to give the corresponding alkyl 2-aminobenzo[b]thiophene-3-carboxylate in excellent yield.

The high-yielding four component reaction is based on the in situ reaction of benzyl chlorides, bromides, or tosylates with dimethyl sulfoxide to the corresponding aldehydes which are further converted using alkyl or benzyl isocyanides and aryl or alkyl carboxylic acids to α-acyloxyamides.

The bridgehead-fused 6:6:6 systems (IV) (11 examples) with one ring-junction nitrogen atom are easily obtained from tetrazine (I), various aldehydes (II), and dimedone (III).

A simple method for the preparation of alkyl 2-aminobenzo[b]thiophene-3-carboxylates is described. Alkyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylates, generated from the Gewald three-component reaction between cyclohexanones, alkyl cyanoacetates and sulfur, undergo dehydrogenation in benzonitrile under an air atmosphere to afford alkyl 2-aminobenzo[b]thiophene-3-carboxylates in good to excellent yields.

A facile one-pot, four-component reaction for the synthesis of pyrrolo[1,2-a]quinolines is described. Knoevenagel condensation reaction of malononitrile and aromatic aldehydes gave 2-arylmethyliden...

The novel 1:1:1:2 addition reaction of phenacyl bromide, malononitrile, isocyanide, and acetylenedicarboxylate provides the polycyclic product (V) as the only one of 16 possible diastereomers.

The title reaction is advantageous with regards to operational simplicity, high yields and readily available starting materials.

The reusability of the employed catalyst, good to excellent yields, short reaction times, and the avoidance of harsh reagents are the main advantages of the introduced method.

Knoevenagel condensation reaction of an aldehyde and Meldrum’s acid produces a 5-arylmethylidene Meldrum’s acid, which undergoes Michael addition of a trialkyl phosphite under solvent-free conditions to afford the title compounds in good yields.

The reaction of isocyanides (II) with dibenzoylacetylene (I) leads to the 1:2 adduct (III) and 2:2 adduct (IV) under mild reaction conditions.

via a three-component reaction of 3-acetylpyran-2,4(3H)-dione, (isocyanoimino)-triphenylphosphorane and aromatic aldehydes

A one-pot three-component synthesis of 6-aryl-8H-dibenzo[d,h][1,3,7,2]dioxazaborecin-8-ones is described. A mixture of 2-aminobenzoic acid, 2-hydroxybenzaldehyde, and arylboronic acid undergo a 1:1:1 addition reaction in CCl4 under microwave irradiation to produce bridgehead bicyclo[4.4.0]boron heterocycles in excellent yields.

The title compounds can be prepared via a one-pot method without any activation or modification of the starting materials and reagents.

An efficient synthesis of aryliminophosphoranes is described. A mixture of an aromatic amine, diethyl azodicarboxylate and triphenylphosphine undergo a Mitsonobu type reaction at ambient temperature in dry dichloromethane to afford aryliminophosphoranes in excellent yields.

Benzyl halides (I) or -tosylates (V) are oxidized to aldehydes under mild Kornblum conditions which then undergo a three-component reaction with various 2-aminopyridines (II) and isocyanides (III) to afford title compounds (IV)/ (VI) in high yields.

The highly fluorescent products may be of interest in the field of bioorganic and medicinal chemistry.

The simple procedure allows the preparation of the heterocyclic scaffold (III) (12 examples), which is of interest in the preparation of tyrosine kinase inhibitors, in good to excellent yields.

The title reaction proceeds under mild conditions and gives the synthetically important succinimides diastereoselectively.

Reactive zwitterionic intermediates formed by the addition of catalytic N-methylimidazole to acetylenic esters are trapped by TOSMIC (I) to give pyrroles in high yields.

The simple procedure including Ph3P=N-NC offers a direct entry to the pharmacologically interesting title compounds (IV).

A simple synthesis of 2-(alkylamino)-5-{alkyl[(2-oxo-2H-chromen-3-yl)carbonyl]amino}-3,4-furandicarboxylates via a one-pot multi-component reaction is described. The reactive 1:1 zwitterionic intermediate generated from the addition of isocyanides to dialkyl acetylenedicarboxylates was trapped at room temperature by coumarin-3-carboxylic acids prepared in situ from a 2-hydroxy aromatic aldehyde and Meldrum’s acid to afford the title compounds in good to excellent yields.

Under ultrasound irradiation and in the presence of H2O/Et2NH, ethyl cyanoacetate or malononitrile can combine with α-methylene carbonyl compounds and elemental sulfur to efficiently yield 2-aminothiophene derivatives within a few minutes. Products are easily obtained by simple filtration because of their spontaneous precipitation in the reaction mixtures.