Enantioselective organocatalytic Friedel-Crafts alkylation reaction of indoles with 5-hydroxyfuran-2(5H)-one: access to chiral γ-lactones and γ-lactams via a Ugi 4-center 3-component reaction

5-Hydroxyfuran-2(5H)-one 1, a readily available renewable resource, was used as an electrophile in the Friedel-Crafts alkylation of indoles catalyzed by a diphenylprolinol silyl ether. Moderate catalyst loading was achieved because of the high reactivity of 5-hydroxyfuran-2(5H)-one 1 in this process. Reduction of the Friedel-Crafts adduct (FC adduct) afforded indoyl lactones in high yield and enantioselectivity. Moreover, the FC adduct was used as a chiral synthon in a diversity-oriented synthesis, as illustrated by its successful engagement in a 4-center 3-component Ugi reaction (U-4C-3CR) to afford chiral five-membered lactams in high yield and enantioselectivity.     

Efficient method for the synthesis of 2-(3-arylbenzo[f]quinolin-2-yl)ethanol derivatives through an unusual ring-opening of THF-involved reaction

An efficient synthesis of 2-(3-arylbenzo[f]quinolin-2-yl)ethanol derivatives by an unusual THF-involved reaction of aromatic aldehyde and naphthalen-2-amine promoted by iodine has been demonstrated with good yields. The ring-opening of THF reaction is proposed in the possible mechanism.     

[Bmim]N3 as an efficient reagent for the Schmidt reactions of ketones,arylaldehydes and aromatic carboxylic acids

Schmidt reaction of arylaldehydes, ketones and aromatic carboxylic acids using task-specific ionic liquid, [bmim]N₃ in the presence of AcOH/H₂SO₄ proceeds at 50–60 °C within 2–4 h to give the corresponding products. Benzaldehydes containing electron releasing groups afforded to the related benzamide derivatives. Benzonitrile derivatives were formed from the reaction of benzaldehydes containing electron withdrawing groups under these conditions. High yields of the related amides and anilines were obtained from the reaction of a variety of ketones and aromatic carboxylic acids, respectively, utilizing this procedure.     

Iron(III) catalyzed direct C–H functionalization at the C-3 position of chromone for the synthesis of fused chromeno-quinoline scaffolds

This communication describes an iron-catalyzed route for the synthesis of 6-substituted chromeno[3,2-c]quinolin-7-one. The method developed does not require any pre-functionalization to execute the pivotal coupling reaction at the C-3 position of flavones. The final step involves the consecutive application of imine formation, C_sp²-C_sp² coupling and oxidation reaction, with aromatic aldehydes and 2-(2-aminophenyl)-4H-chromen-4-one as the reactants. Presence of electron donating/withdrawing groups was well tolerated in the aldehydes and the method developed could also be extended to other substituted 2-(2-aminophenyl)-4H-chromen-4-one’s. This is the first report of synthesis of 6-substituted chromeno[3,2-c]quinolin-7-one’s via direct functionalization of the C-3 site of flavones.     

超声波和无溶剂条件下1-芳基-5-二茂铁基-1,4-二烯-3-酮的合成

在室温下使用超声波或无溶剂条件下,4-二茂铁基-3-烯-2-酮和芳香醛的羟醛缩合能以83％～97％的收率得到1-芳基-5-二茂铁基-1,4-二烯3-酮。这种方法具有操作简单,反应条件温和,产率高和低能耗等优点。     

双消除法一锅简便合成1－丙炔基芳香化合物

报道了一种便捷合成1-丙炔基芳香化合物的新方法. 在充分探讨反应条件的基础上, 利用硫试剂乙基苯基砜与芳香醛组合, 采用双消除反应成功地一锅合成了一系列1-丙炔基芳香化合物1a～1s. 运用此法不仅合成出一些含有醚键、萘环、杂环以及含有两个1-丙炔基的化合物, 重要的是芳环上含有卤原子(Br和I)的化合物也能顺利地合成出来. 该方法原料易得, 操作简单, 产物容易分离纯化并且产率理想.     

Chiral Phosphoric Acid Catalyzed Asymmetric Ugi Reaction by Dynamic Kinetic Resolution of the Primary Multicomponent Adduct

Reaction of isonitriles with 3‐(arylamino)isobenzofuran‐1(3H)‐ones in the presence of a catalytic amount of an octahydro (R)‐binol‐derived chiral phosphoric acid afforded 3‐oxo‐2‐arylisoindoline‐1‐carboxamides in high yields with good to high enantioselectivities. An enantioselective Ugi four‐center three‐component reaction of 2‐formylbenzoic acids, anilines, and isonitriles was subsequently developed for the synthesis of the same heterocycle. Mechanistic studies indicate that the enantioselectivity results from the dynamic kinetic resolution of the primary Ugi adduct, rather than from the C?C bond‐forming process. The resulting heterocycle products are of significant medicinal importance.     

A clean synthesis of oxazino[5,6-f]quinolinone and naphtho[1,2-e]oxazinone derivatives

A clean, simple, one-pot, and efficient synthesis of 1,2-dihydro-1-aryl[1,3]oxazino[5,6-f]quinolin-3-one and 1,2-dihydro-1-arylnaphtho[1,2-e]-[1,3]oxazine-3-one derivatives was accomplished in good yields via reaction between 6-quinolinol or 2-naphthol, aromatic aldehydes, and methyl carbamate in aqueous medium catalyzed by TEBA (triethylbenzylammonium chloride).     

在三乙基苄基氯化铵相转移催化下水相中(E)-3-亚苄基-2,3-二氢吲哚-2-酮衍生物的合成

以芳醛和2,3-二氢吲哚为原料, 以水为溶剂, 在室温以三乙基苄基氯化铵为催化剂合成了一系列的(E)-3-亚苄基-2,3-二氢吲哚-2-酮衍生物. 该方法具有反应条件温和、立体选择性好、产率高(72%～96%)和环境友好等优点. 产物的结构通过熔点, IR, ¹H NMR和元素分析表征.     

Direct organocatalytic in situ generation of novel push-pull dienamines: application in tandem Claisen-Schmidt/iso-aromatization reactions

A new, green, regioselective, one-step, tandem reaction of an aldehyde possessing a non-enolizable carbonyl function with a highly substituted cyclohex-2-enone, under amine catalysis afforded highly substituted phenols or 2-arylidenecyclohexanones, respectively. The yields and regioselectivities were good. Evidence for a pathway involving formation of novel push-pull dienamines is presented along with examples demonstrating the amenability of the process to combinatorial chemistry.     

Spectrophotometric Determination and Kinetic Studies of Condensation of Aromatic Aldehydes with 7,9‐Dioxo‐6,10‐dioxaspiro[4.5]decane

The condensation reaction rates of 7,9‐dioxo‐6,10‐dioxaspiro[4.5]decane with aromatic aldehydes in chloroform in the presence of piperidine has been investigated spectrophotometrically at 25–50 °C. The reaction follows overall second order kinetics, first order in each of the reactants and zero order with respect to piperidine. The rate of condensation increases with the presence of electron withdrawing groups on the aromatic ring of the aldehyde. From the dependence of the rate constants on temperature, activation parameters have been calculated. Plot of ΔH# versus ΔS# for the reaction gave a good straight line with an isokinetic temperature of 367.55 K. Based on this reaction, determination often aromatic aldehydes in a concentration range of 2.65–69.2 μg/mL is proposed.     

Ugi/xanthate cyclizations as a radical route to lactam scaffolds

The combination of Ugi reaction and xanthate radical cyclization onto alkenes allows an easy access to various highly functionalized heterocycles. The addition of chloroacetic acid to primary amines, aldehydes and isocyanides in methanol followed by the treatment with potassium ethyl xanthate, affords the xanthate Ugi adducts in good yields. These adducts were then submitted to radical cyclization conditions with dilauroyl peroxide as initiator. The choice of an alkene function properly located on the amine or the aldehyde permits the formation of 5- to 8-membered rings in moderate to good yields.     

A novel sugar based intramolecular Ugi 3CC for the N-alkyl-3-oxo-4-aryl-octahydrofuro[2,3-f][1,4]oxazepine-5-carboxamides

An intramolecular Ugi reaction of 3-carboxy tethered sugar aldehyde with aryl amines and isocyanides has been accomplished to produce a novel class of carbohydrate derivatives, 3-oxo-4-aryl-octahydrofuro[2,3-f][1,4]oxazepine-5-carboxamides in good yields. The stereochemistry of the products was assigned by NMR studies. This is the first report on intramolecular Ugi reaction of 3-carboxy tethered sugar aldehyde, aryl amine, and isonitrile.     

Domino Carbopalladation/CH Functionalization Sequence: An Expedient Synthesis of Bis‐Heteroaryls through Transient Alkyl/Vinyl–Palladium Species Capture

A microwave‐assisted highly efficient intermolecular domino carbopalladation/C?H functionalization sequence has been developed to access bis‐heteroaryl frameworks in a single operation. The reaction involves carbopalladation of the halogenated acrylamides or phenylpropiolamides by the Pd(0) catalysis, followed by the direct (hetero)arylation to give products with good to excellent yields. The synthetic utility of this method was also extended towards the application of the Ugi‐adduct as the starting material.     

The oxidation of aldehydes to acids with calcium hypochlorite [Ca(OCl)2]

Calcium hypochlorite is an efficient reagent for the oxidation of aldehydes to the corresponding acids. Reactions are carried out at ambient temperature in aqueous acetonitrile-acetic acid solution. Aliphatic aldehydes and aromatic aldehydes with electron withdrawing groups afford good to excellent yields. Nuclear chlorination is the preferred reaction in aromatic aldehydes with electron donating groups.     

One-pot synthesis of 1, 3-thiazolidin-4-one using Bi(SCH2COOH)3 as catalyst

A catalytic multi-component reaction involving aromatic amine,aromatic aldehydes,mercapto acid as substrates and Bi（SCH₂COOH）₃ as catalyst under solvent free conditions,afforded thiazolidin-4-one in good yields.The efficiency of the catalyst was proved with a variety of substrates,ranging from electrondeficient to electron-rich aldehydes.     

One-pot synthesis of oxoisoindoline-1,2,3-triazole hybrid by a Ugi–click reaction

1,2,3-Triazole-3-oxoisoindoline-1-carboxamide system was successfully synthesized by using a combination of Ugi and click reactions. This two-step, one-pot synthesis was started by the reaction of 2-formyl benzoic acid, propargyl amine, and cyclohexyl isocyanide in ethanol. The resultant Ugi adduct underwent a copper-catalyzed click reaction, producing the desired products in good yields.     

A clean synthesis of oxazino[5,6-<Emphasis Type="Italic">f</Emphasis>]quinolinone and naphtho[1,2-<Emphasis Type="Italic">e</Emphasis>]oxazinone derivatives

A clean, simple, one-pot, and efficient synthesis of 1,2-dihydro-1-aryl[1,3]oxazino[5,6-f]quinolin-3-one and 1,2-dihydro-1-arylnaphtho[1,2-e]-[1,3]oxazine-3-one derivatives was accomplished in good yields via reaction between 6-quinolinol or 2-naphthol, aromatic aldehydes, and methyl carbamate in aqueous medium catalyzed by TEBA (triethylbenzylammonium chloride). Correspondence: Mohammad Hossein Mosslemin, Department of Chemistry, Islamic Azad University, Yazd 8916871967, Iran.     

Novel succinct routes to quinoxalines and 2-benzimidazolylquinoxalines via the Ugi reaction

This Letter reveals a unique, user-friendly, concise two-step, one-pot protocol for the synthesis of highly substituted quinoxalines. Conducting the Ugi reaction with appropriately functionalized classical Ugi reagents with subsequent acid treatment of the Ugi adduct affords collections of diversified quinoxalines in good to excellent yields. The methodology exploits what may be viewed as a ‘convertible carboxylic acid’, which in addition may be captured in an intramolecular sense to generate structurally complex 2-benzimidazolylquinoxalines in a mere two steps.     

A facile method for building fused quinoxaline-quinolinones via an acidless post-Ugi cascade reaction

A series of quinolino[3,4-b]quinoxalin-6(5H)-ones have been synthesized using an Ugi/deprotection/cyclization(UDC) strategy, followed by a nucleophilic aromatic substitution reaction. This facile microwave-assisted method provided good yields and could potentially be used for the construction of a diverse library of quinolino[3,4-b]quinoxalin-6(5H)-ones for high-throughput screening in medicinal chemistry.