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An asymmetric assembly of δ-lactams was realized via the NHC-catalyzed formal [4 + 2] annulation of acylhydrazones and 2-bromo-2-enals bearing γ-H. The advantages of this protocol include high enantioselectivity, good yields, mild reaction conditions and potential biological significance of the final products.

A NHC-catalyzed [4 + 2] cyclization of 2-bromo-2-enal bearing γ-H with 3-alkylenyloxindoles under mild reaction conditions gives spirocarbocyclic oxindoles containing one quaternary carbon in moderate to good yields with high diastereoselectivities. The easy availability of the starting materials, the concise assembly and the potential utilization value of the products make this strategy attractive in molecular biology and pharmacy.

This manuscript discloses an efficient construction of the spirocyclic oxindole-dihydropyranone scaffold via the N-heterocyclic carbene (NHC)-catalyzed oxidative γ-functionalization of α,β-unsaturated aldehydes bearing γ-H with isatin derivatives. The ready availability of the starting materials, easy work-up, mild reaction conditions and the potential utilization value of the products make this strategy attractive.

Carbenes ring true: N-Heterocyclic carbene (NHC) catalyzed reactions of α-bromo-α,β-unsaturated aldehydes/α,β-dibromoaldehydes with 1,3-dinucleophilic reagents, such as 1,3-dicarbonyl compounds, β-enamino ketones, and β-enamino esters through umpolung processes gave functionalized 3,4-dihydropyranones and 3,4-dihydropyridinones. The availability of the starting materials, lack of external oxidant, and usefulness of the products make this strategy attractive., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A convenient, rapid and electrochemical one‐pot protocol was developed successfully for the preparation of pyrazolo[3,4‐b]‐quinoline derivatives. The reaction is carried out in a 25 mL three neck flask equipped with graphite electrode as anode and iron electrode as cathode (electrode area of 1 cm2) with sodium bromide as supporting electrolyte at room temperature in ethanol. Fourteen pyrazolo‐[3,4‐b]‐quinoline derivatives were synthesized by use of various aldehyde (including aryl aldehydes and aliphatic aldehydes), dimedone and 5‐amino‐3‐methyl‐1‐phenylpyrazole as substrates in good yields (76–86 %) with a constant current of 30 mA after 0.14 F/mol of electricity passed. All aimed products were characterized by IR, 1H NMR and HRMS. Notably, the presented method features ecologically sound, simple experimental procedure and good yields. [ABSTRACT FROM AUTHOR]

An electrochemical synthesis of 4-substituted-cyclopenta[ b]pyran derivatives through the one-pot condensation of cyclopentane-1,3-dione, malononitrile, and aldehydes is reported. The reaction is carried out in an undivided cell in the presence of sodium bromide as a supporting electrolyte. Notably, the presented method features high efficiency, excellent yield, and simple experimental procedure. [ABSTRACT FROM AUTHOR]

A series of novel 7,9-dihydrothieno[3′,2′:5,6]pyrido[2,3- d]pyrimidine-4,6(3 H,5 H)-dione derivatives were synthesized efficiently via the catalyst-free reaction of aldehyde, ethyl 2,4-dioxotetrahydrothiophene-3-carboxylate, and 2,6-diaminopyrimidine-4(3 H)-one through the sequence of deethoxycarbonylation and three-component condensation in aqueous media. This protocol featured mild reaction conditions, high yields, easy work-up, and environmentally friendly procedure. [ABSTRACT FROM AUTHOR]

A series of novel benzo[ f]thiopyrano[3,4- b]quinolin-11(8 H)-one derivatives were synthesized via the reaction of aryl aldehyde, 2 H-thiopyran-3,5(4 H,6 H)-dione, and β-naphthylamine in glacial . This protocol features mild reaction conditions, high yields, and short reaction time. [ABSTRACT FROM AUTHOR]

2,3-Diaryl quinoxaline derivatives have been efficiently synthesized by cascade, metal-free, and solvent-free reaction of aryl aldehydes with aryl 1,2-diamines initiated by N-heterocyclic carbene. Compared with reported methods, this procedure has the advantages of easy work-up, reduced energy consumption, and elimination of solvent waste, hazards, and toxicity. A group of potentially bioactive compounds has been prepared for biomedical screening. [ABSTRACT FROM AUTHOR]

A concise synthesis of 6-amino-4-aryl-3-(trifluoromethyl)-1,4-dihydro-1-phenylpyrano[2,3- c]pyrazole-5-carbonitriles was performed effectively in aqueous media without catalyst by the reaction of aryl aldehydes, malononitrile, and 1-phenyl-3-(trifluoromethyl)-1 H-pyrazol-5(4 H)-one. This method has the advantages of mild condition, avoidance of the use of catalysts, high yields, and environmentally benign procedure. [ABSTRACT FROM AUTHOR]

Abstract: An electrochemical strategy to the assembly of tricyclic spiro dihydrofuran scaffold via the reaction of aryl aldehyde and dimedone has been developed successfully. This protocol has the advantages of high yields, wide application scope and an environmental benign procedure compared with the reported methods. [Copyright &y& Elsevier]

A series of novel tetrazolo[1,5- a]thiopyrano[3,4- d]pyrimidine derivatives were synthesized by reaction of aryl aldehyde, 2 H-thiopyran-3,5(4 H,6 H)-dione, and 5-aminotetrazole under solvent-free conditions. The features of this procedure are mild reaction conditions, high yields, and operational simplicity. [ABSTRACT FROM AUTHOR]

A series of 2-(phenylamino)-4-(trifluoromethyl)-1,6-dihydropyrimidine derivatives were synthesized efficienly via the reaction of aryl aldehyde, ethyl 4,4,4-trifluoro-3-oxobutanoate and 1-phenylguanidine carbonate catalyzed by sulfamic acid under solvent-free conditions. This protocol has the advantages of mild condition, high yields and environmentally benign procedure. [ABSTRACT FROM AUTHOR]

Abstract: A new cascade strategy to the synthesis of 2,3-diarylated indoles via the metal-free reaction of aryl aldehyde and aryl amine triggered by N-heterocyclic carbene (NHC) under solvent-free conditions, has been disclosed. The protocol has the advantages of easy work-up, high yields, wide application scope, and an environmentally benign procedure compared with the reported methods. [Copyright &y& Elsevier]

An efficient synthesis of 7-aryl-1,1-dioxothieno[3,2- b]pyran derivatives via the reaction of aryl aldehyde, tetrahydrothiophene-3-one-1,1-dioxide and malononitrile or ethyl 2-cyanoacetate was performed at room temperature catalyzed by ammonium acetate under solvent-free conditions. Compared with the conventional methods, this protocol features mild reaction conditions, high yields, and eco-friendliness. J. Heterocyclic Chem., (2011). [ABSTRACT FROM AUTHOR]

The title compounds (IV) are efficiently obtained by three-component condensation of aldehydes, 2,4-dioxotetrahydrothiophene-3-carboxylate, and 2,6-diaminopyrimidine-4(3H)-one under environmentally-friendly and mild reaction conditions. [ABSTRACT FROM AUTHOR]

A catalyst-free synthesis of 6,9-dihydro-[1,3]dioxolo[4,5- g ]thieno[3,4- b ]quinolin-8(5 H )-ones as novel analogues of podophyllotoxins was developed by a three-component reaction of aldehydes, ethyl 2,4-dioxotetrahydrothiophene-3-carboxylate and 3,4-(methylenedioxy)aniline. This methodology not only provides new chemical library for the screening of anticancer activity, but also features excellent isolated yields, short reaction time, simple work up procedure and little environmental impact. [ABSTRACT FROM AUTHOR]

An alternative approach to 2,3-diarylated benzofurans (III) by virtue of the sequential catalysis of NHC and Pd from substituted 2′-bromodiphenylbromomethanes (I) and aryl aldehydes (II) is developed. [ABSTRACT FROM AUTHOR]

Chemical formulas explaining the oxidative gamma-addition of alpha-Beta-unsaturated aldehydes to isatins to synthesize spirocyclic oxindole-dihydropyranones are presented.