Catalyst‐Free Reaction in Water: Synthesis of Functionalized Tetrahydroindole Derivatives via Three‐Component Domino Reaction

An environmentally benign and efficient method has been developed for the synthesis of functionalized tetrahydroindole derivatives in aqueous media under catalyst‐free conditions, by simply combining a phenylglyoxal monohydrate, an enaminone, and a barbituric acid. The advantages of this method are that it is catalyst free, has an easy workup, provides good yields, and uses water as solvent, which make this procedure facile and practical.     

An Efficient Synthesis of New Dispiropyrrolidine Derivatives via Three‐Component 1,3‐Dipolar Cycloaddition Reaction

A series of new dispiropyrrolidine derivatives were synthesized via the three‐component 1,3‐dipolar cycloaddition reaction of azomethine ylides generated in situ by the decarboxylative condensation of acenaphthenequinone and sarcosine or l ‐thioproline with 5‐benzylidene‐1,3‐dimethylpyrimidine‐2,4,6‐trione. The structures of the products were identified by IR, ¹H‐NMR, and HRMS spectra.     

Catalytic Three‐Component Domino Reaction for the Preparation of Trisubstituted Oxazoles

Multicomponent reactions are attractive for assembling functionalized heterocyclic compounds. To this end, an efficient gold‐catalyzed three‐component domino reaction to form oxazoles directly from imines, alkynes, and acid chlorides is presented. The reaction proceeds in a single synthetic step by using a gold(III)–N,N′‐ethylenebis(salicylimine) (salen) catalyst to give trisubstituted oxazoles in up to 96 % yield. The substrate scope, a mechanistic study exploring the role of the gold catalyst, and the synthetic applications of the oxazole products are discussed.     

Efficient One‐Pot Synthesis of Novel Spirooxindole‐Fused Phosphorous Heterocycle Derivatives by a Three‐Component Domino Reaction

A highly efficient, catalyst‐free, and regioselective synthesis of structurally diverse spirooxindole‐fused phosphorous heterocycle derivatives was constructed in good yields by means of a three‐component domino reaction of isatins, dichlorophenylphosphine or phenyl phosphorodichloridite, and o‐aminophenol in tetrahydrofuran reflux. The advantages of this method include high efficiency, mild reaction conditions, and environmentally benign reagents. These spirooxindole‐fused phosphorous heterocycles are promising candidates for drug discovery.     

Palladium‐Catalyzed Three‐Component Cascade Reaction: Facial Access to Densely Functionalized Indolizines

A palladium‐catalyzed three‐component cascade reaction of 2‐(2‐enynyl)pyridines with nucleophiles and allyl halides has been developed, enabling the synthesis of densely functionalized indolizines in moderate to good yields. The newly developed methodology offers several practical advantages, including operational simplicity, ready availability of starting materials, and mild reaction conditions.     

An Efficient Synthesis of Polyfunctionalized Indole Derivatives via Three‐component Domino Reaction Catalyzed by L‐Proline

A facile and efficient one‐pot procedure for the preparation of indeno[1,2‐b]indole derivatives via three‐component domino reaction of ninhydrin, enaminones, and malononitrile catalyzed by L‐proline is described. In this reaction, two rings and four bonds were formed by one‐pot.     

An Efficient Three‐Component Synthesis of Pyranoquinoline Derivatives

Pyranoquinoline derivatives have been synthesized via three‐component reaction of 4‐hydroxy‐1‐methyl‐2(1H)‐quinolinone and dialkyl acetylenedicarboxylates in the presence of nucleophiles such as alkyl isocyanides and triphenylphosphine.     

Synthesis of Spiro Pyrrolobenzothiazole Derivatives via a Three‐Component Reaction

A novel three‐component reaction involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, acetylenic esters and 1,3‐dicarbonyl compounds such as (1,3‐dimethylbarbituric acid or 1,3‐indanedione) leading to the synthesis of spiro pyrrolobenzothiazole derivatives. The reactions proceeded smoothly at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation. The structures of the synthesized compounds have been characterized by spectral studies.     

Synthesis of Chromene Derivatives via Three‐Component Reaction of 4‐hydroxycumarin Catalyzed by Magnetic Fe3O4 Nanoparticles in Water

An easy and effective procedure for one‐pot three components coupling of 4‐hydroxycumarin, isothiocyanates, and isocyanides in water by employing magnetically recoverable Fe₃O₄ nanoparticles is described. Variety of chromene were produced a derivatives in high yields by using of this procedure. The catalyst can be recovered and recycled without a considerable decrease in the catalytic activity.     

Application of Functionalized N,S‐Ketene Acetals–Microwave‐Assisted Three‐Component Domino Reaction for Rapid Direct Access to Imidazo[1,2‐a]pyridines

Imidazo[1,2‐a]pyridines have been successfully synthesized in moderate to good yields via a tandem three‐component reaction of ethyl 2‐(3‐oxo‐3‐arylpropanethioamido)acetates with aromatic aldehydes and malononitrile by means of microwave irradiation using DABCO as the catalyst. The advantages of this method including high chemo‐ and regioselectivity make this new strategy highly attractive.     

A Highly Diastereoselective Three‐component Domino Reaction in Water Yielding Poly‐substituted 4,5‐Dihydropyrroles

An efficient methodology for highly diastereoselective synthesis of poly‐substituted 4,5‐dihydropyrrole derivatives from readily available common reactants in water has been developed. During domino processes, the formation of pyrrole skeleton and its C2‐hydroxylation and C3‐arylamination were readily achieved via metal‐free [3+2] heterocyclization in a one‐pot operation.