Short-step synthesis of droloxifene via the three-component coupling reaction among aromatic aldehyde, cinnamyltrimethylsilane, and β-chlorophenetole

A short-step route for the preparation of droloxifene has been established via the novel three-component coupling reaction among 3-pivaloyloxybenzaldehyde, cinnamyltrimethylsilane, and β-chlorophenetole, the successive installation of the side-chain part, and the base-induced migration of the double bond. The present synthesis of tetra-substituted ethylene moieties is a widely applicable strategy for producing a variety of SERMs (selective estrogen receptor modulators) and SARMs (selective androgen receptor modulators), such as tamoxifen, raloxifene, and other compounds that can lead to new drugs.     

One-pot synthesis of tetrahydrofuran derivatives via a divalent palladium-catalyzed three-component coupling

Under divalent palladium catalysis, a three-component coupling reaction for synthesizing tetrahydrofuran derivatives has been established. The reaction involves the intramolecular carbopalladation of an alkyne with a carbanion which was generated from the addition of an alkoxide ion to an alkene derivative, followed by allylic chloride insertion to the CPd bond and quenching the CPd bond by β-heteroatom elimination in the presence of excess chloride ions.     

Gold(III) Salen complex-catalyzed synthesis of propargylamines via a three-component coupling reaction

[reaction: see text] Propargylamines have been synthesized by a gold(III) salen complex-catalyzed three-component coupling reaction of aldehydes, amines, and alkynes in water in excellent yields at 40 degrees C. With chiral prolinol derivatives as the amine component, excellent diastereoselectivities (up to 99:1) have been attained. This coupling reaction has been applied to the synthesis of propargylamine-modified artemisinin derivatives with the delicate endoperoxide moieties remaining intact. Cytotoxicities with IC(50) values up to 1.1 microM against a human hepatocellular carcinoma cell line (HepG2) were exhibited by these artemisinin derivatives.     

A base-mediated three-component coupling reaction for the synthesis of phosphorohydrazones

A simple and efficient three-component coupling reaction for the synthesis of phosphorohydrazones was developed. Both aldehydes and ketones participated in the reaction to afford the corresponding phosphorohydrazones in moderate-to-good yields. Moreover, a novel P–N ligand was synthesized by this method, which can act as a fluorescent sensor for iron ion.     

Convergent synthesis of dendrimers via the Passerini three-component reaction

Tuning properties by programming the surface functional group composition of surface-block dendrimers has been limited to dendrimers with only two types of surface functionality (i.e., surface-diblock dendrimers). The Passerini reaction provides dendrimer products from precursor dendrons in reasonable yields. This proof-of-principle experiment opens the door to making surface-triblock dendrimers.     

An efficient synthesis of thiazol-2-imine derivatives via a one-pot,three-component reaction

A simple and highly efficient one-pot, three-component procedure for the synthesis of thiazol-2-imines, via the reaction of aromatic α-bromoketones, primary amines, and phenyl isothiocyanate in the presence of a catalytic amount of triethylamine, is described.     

Green synthesis of novel chalcone and coumarin derivatives via Suzuki coupling reaction

Chalcones and coumarins are important naturally occurring plant constituents and display a wide range of pharmacological and biological activities. In an environmentally benign approach, synthesis of biphenyl chalcone and coumarin derivatives was successfully accomplished via Suzuki coupling by using PEG-400 as a solvent under microwave irradiation. Salient feature of this methodology includes: short reaction time, good to excellent yields, and prominent tolerance of different functional groups.     

Synthesis of allyl cyanamides and N-cyanoindoles via the palladium-catalyzed three-component coupling reaction

The palladium-catalyzed three-component coupling reaction (TCCR) of aryl isocyanides, allyl methyl carbonate, and trimethylsilyl azide was conducted in the presence of Pd(2)(dba)(3).CHCl(3) (2.5 mol %) and dppe (1,2-bis(diphenylphosphino)ethane) (10 mol %). Allyl aryl cyanamides with a wide variety of functional groups were obtained in excellent yields. This palladium-catalyzed TCCR was further utilized for the synthesis of N-cyanoindoles. The reaction of 2-alkynylisocyanobenzenes, allyl methyl carbonate, and trimethylsilyl azide in the presence of Pd(2)(dba)(3).CHCl(3) (2.5 mol %) and tri(2-furyl)phosphine (10 mol %) at higher temperatures afforded N-cyanoindoles in good to allowable yields. (eta(3)-Allyl)(eta(3)-cyanamido)palladium complex, an analogue of the bis-pi-allylpalladium complex, is a key intermediate in the TCCR, and a pi-allylpalladium mimic of the Curtius rearrangement is involved to generate the (eta(3)-allyl)(eta(3)-cyanamido)palladium intermediate.     

Gold-mediated bifunctional modification of oligosaccharides via a three-component coupling reaction

An efficient modular approach for single-site incorporation of two independent functionalities (amines and alkynes) into aldehyde-containing oligosaccharides concurrently by using a one-pot gold-mediated three-component coupling reaction in aqueous medium under mild conditions has been developed.     

Synthesis of Mannich type products via a three-component coupling reaction

The reactions of alkyl nitriles, acetyl chloride, aldehydes and β-ketoesters or simple ketones was studied for the one-pot synthesis of β-acetamido carbonyl compounds. It was observed that the reaction proceeds in the absence of Lewis acids. However, a Lewis acid catalyzes the reaction and several were tested. It was found that whereas Cu(OTf)₂ is suitable for the coupling of β-ketoesters with aldehydes, Sc(OTf)₃ is the best for ketones. A possible mechanism is proposed based on the isolation and characterization of an intermediate.     

Efficient stereoselective synthesis of benzoxazines via copper-catalyzed three-component coupling reactions

A convenient one-pot synthesis of 1,4-benzoxazines via three-component coupling and subsequent O-cyclization is reported. The present reaction provides an efficient protocol to functionalized 1,4-benzoxazine derivatives in good to high yields from aldehydes, amines and alkynes. Furthermore, the O-annulation process is completely regio- and stereoselective, only the six-membered rings and its Z-isomers were obtained.     

Recent topics in annulation reaction via double CH bond cleavage and double CC bond formation

Cyclic compounds have been consistently key components in organo functional molecules. To construct cycles, a catalytic two CH bond-cleaving annulation is one of the most ideal and straightforward methods with atom and step economies. Recently, many patterns of such annulation reactions have been developed, which construct a variety of cyclic compounds consisted of from simple to complex frameworks. This Digest focuses a recent progress in two or more than three CH bond-cleaving annulation reactions and is outlined as follows: (1) intramolecular annulation, (2) intermolecular annulation via double CH bond cleavages in one molecule, and (3) intermolecular annulation via double CH bond cleavages in two molecules.     

A novel one-pot three-component synthesis of benzofuran derivatives via Strecker reaction: Study of antioxidant activity

Abstract

A three-component Strecker-type reactions was applied for the synthesis of benzofuran derivatives through the reaction of 1-(6-hydroxy-2-isopropenyl-1-benzofuran-yl)-1-ethanone (euparin), primary amines and trimethylsilyl cyanide (TMSCN) in the presence of catalytic amount of ZnO-nanorods (ZnO-NR) and piperidine in acetonitrile at room temperature. The method has proved to be synthetically simple, and effective with high atom economy and yield. The catalyst also revealed significant reusability. Moreover, the antioxidant activity and free radical scavenging capacity of the newly synthesized such as 4a, 4c, 6a and 6c was screened using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays and compared with hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). These compounds exhibit good DPPH radical scavenging and ferric reducing antioxidant power (FRAP) assays.     

Light promoted aqueous phase amine synthesis via three-component coupling reactions

By applying a simple TiO₂–(NH₄)₂S₂O₈ system and promoted by UV light, the three-component reactions of cyclic ether, aniline and aldehyde can be progressed efficiently. 29 substituted amines with different structures were synthesized with up to 97% isolated yields. Isotope effect study revealed that the rate-determining step might be the nucleophilic addition step but not radical generation.     

Palladium-catalyzed synthesis of highly substituted endocyclic enol lactones via a three-component coupling reaction in an ionic liquid

[reaction: see text] A new, efficient ionic liquid based synthetic procedure was developed for the preparation of highly substituted endocyclic enol lactones via the carbonylation coupling reactions of alkynes and 1,3-diketones in ionic liquid. The reactions proceeded in excellent regioselectivity and in reasonably good yields. The catalyst system can be recycled five times with only modest loss of its catalytic activity.     

Enantioselective synthesis of 3,3'-dihydropyrryl-spirooxindoles via an organocatalytic three-component reaction

An organocatalytic three-component reaction of isatins, malononitrile and isocyanoacetates provided 3,3'-dihydropyrryl-spirooxindoles in excellent yields and enantioselectivities. The products could be readily converted to valuable 3,3'-pyrrolidinyl-spirooxindoles.     

A novel three-component reaction for the synthesis of new 4-azafluorenone derivatives

Reaction of arylidenemalononitriles, 1,3-indanedione, and mercaptoacetic acid or 4-methylbenzenethiol is successfully carried out using microwave heating. It is an efficient and promising synthetic strategy to build the indenopyridine skeleton.