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p-TsOH promoted annulation reaction of 3-(indol-3-yl)maleimides and (indol-2-yl)diphenylmethanols in chloroform afforded functionalized pyrrolo[3′,4′:6,7]cyclohepta[1,2-b:4,5-b′]diindoles in satisfactory yields, in which a formal [4+3] cycloaddition and an unprecedented rearrangement of the maleimide motif from the C3- to C2-position of the indole ring was firstly observed. Alternatively, the similar reaction of 3-(indol-3-yl)maleimides and 3-hydroxy-3-(indol-3-yl)-indolin-2-ones in acetonitrile gave functionalized spiro[indoline-3,9′-pyrrolo[3′,4′:4,5]cyclopenta[1,2-b]indole] in good yields and with high diastereoselectivity. On the other hand, p-TsOH promoted reaction of 3-(indol-3-yl)maleimides and 2-hydroxy-2-(indol-3-yl)-indene-1,3-diones gave functionalized spiro[indene-2,9′-pyrrolo[3′,4′:4,5]cyclopenta[1,2-b]indoles] as major products and spiro[indene-2,9′-pyrrolo[3′,4′:6,7]cyclohepta[1,2-b:4,5-b′]diindoles] as minor products. [ABSTRACT FROM AUTHOR]

Triethylamine promoted cycloaddition reaction of phenacylmalononitriles and o-hydroxychalcones in ethanol at room temperature gave multifunctionalized cyclopent-3-ene-1-carboxamides in good yields and with high diastereoselectivity. More importantly, the similar reaction of phenacylmalononitriles and chalcone o-enolates in ethanol at room temperature afforded functionalized 2-oxabicyclo[2.2.1]heptane derivatives in satisfactory yields and with high diastereoselectivity. A rational domino reaction was tentatively proposed to explain the selective formation of different cyclic compounds and the diastereoselectivity of the reaction. [ABSTRACT FROM AUTHOR]

Triethylamine promoted one-pot three-component reaction of alkyl glycinate hydrochloride, dialkyl but-2-ynedioate and 2-(2-hydroxybenzylidene)-1,3-indanediones in ethanol at room temperature efficiently resulted in unique 8a 14-(epoxymethano)indeno[1′,2′:2,3]chromeno[4,3-a]pyrrolizines in satisfactory yields. On the other hand, the base promoted four-component reaction of dialkyl but-2-ynedioate, salicylaldehydes, 1,3-indanediones and secondary α-amino acids such as proline, thiazolidine-4-carboxylic acid and sarcosine in refluxing ethanol gave complex N,O,S-containing polyheterocyclic compounds in good yields. The reaction mechanism included a cascade reaction process of the in situ generation of a special kind of azomethine ylide, 1,3-dipolar cycloaddition and annulation of phenoxide. [ABSTRACT FROM AUTHOR]

The one‐pot three‐component reaction of L‐proline, isatins and 1‐(2‐hydroxyphenyl)‐3‐phenylprop‐2‐en‐1‐ones and sequential reaction with methyl propiolate in refluxing methanol resulted in novel functionalized spiro[chromane‐2,3′‐indoline]‐2′,4‐diones as major products and spiro[chromeno[3,2‐d]azocine‐2,3′‐indolin]‐3‐ yl)acrylate as minor products. On the other hand, the similar one‐pot‐three‐component reaction of L‐proline, isatins and 3‐(2‐hydroxyphenyl)‐1‐phenylprop‐2‐en‐1‐ones and sequential reaction with methyl propiolate in refluxing acetonitrile predominately afforded the unique 6b,14‐(epoxy[1,2]benzeno)pyrrolo[1′,2′:1,2]azocino[4,5‐c]quinoline‐8‐carboxylates in satisfactory yields. [ABSTRACT FROM AUTHOR]

The DABCO promoted domino reaction of 1‐(2‐hydroxyphenyl)‐3‐phenylprop‐2‐en‐1‐ones and alkyl propiolate or dialkyl but‐2‐ynedioate in toluene at high temperature resulted in methyl 3‐(2‐hydroxybenzoyl)‐1‐naphthoates or dimethyl 3‐(2‐hydroxybenzoyl)naphthalene‐1,2‐dicarboxylate in moderate to good yields. The hydroxyl group played a crucial rule in the reaction. The reaction mechanism of this formal [4+2] cycloaddition reaction was believed with initially formation of methyl 3‐(2‐cinnamoylphenoxy)acrylate, intramolecular Diels‐Alder reaction, ring‐opening of benzo[b]xanthene and aromatization process. [ABSTRACT FROM AUTHOR]

TEMPO promoted cycloaddition reaction of different kinds of ketohydrazones or aldohydrazones with 3-phenacylideneoxindoles showed very interesting molecular diversity according to the chemical structures and reaction conditions. The reactions with 1-(3,4-dihydronaphthalen-1-ylidene)-2-arylhydrazines or 1-cyclohexylidene-2-arylhydrazines in acetonitrile at 80 °C afforded functionalized spiro[benzo[h]cinnoline-3,3′-indolines] or spiro[cinnoline-3,3′-indolines] via aza-Diels–Alder reaction of the in situ generated 1,2-diaza-1,3-diene. The reactions with 2-(2-phenylethylidene)-1-arylhydrazines in dioxane afforded functionalized spiro[indoline-3,3′-pyrazoles] though a [3+2] cycloaddition reaction of the in situ generated 1,3-dipolar azomethine imine. On the other hand, a similar reaction in acetonitrile unusually resulted in pyrazole derivatives via sequential [3+2] cycloaddition and a ring-opening process. [ABSTRACT FROM AUTHOR]

The acetic acid catalyzed three‐component reaction of pyrrolidine, aromatic aldehydes and 4‐arylidene‐5‐methyl‐2‐phenylpyrazol‐3‐one in refluxing toluene gave functionalized 7′‐(E)‐benzylidenespiro[pyrazole‐4,1′‐pyrrolizines] in good yields and with high diastereoselectivity. The similar reaction with 2‐arylidene‐N,N'‐dimethylbarbiturates resulted in mixture of Z/E‐isomers of 7′‐ arylidenespiro[pyrimidine‐5,1′‐pyrrolizines] in good yields. However, the three‐component with N‐phenylmaleimides and sequential oxidation with DDQ reaction gave 8‐(E)‐arylidenedihydropyrrolo[3,4‐a]pyrrolizines in satisfactory yields. The reaction mechanism included sequential β‐C−H functionalization of pyrrolidine, generation of conjugated azomethine ylides, and sequential [3+2] cycloaddition with active alkenes. [ABSTRACT FROM AUTHOR]

Spiro[indoline‐3,7′‐pyrrolo[1,2‐a]azepines] were conveniently synthesized in satisfactory yields and with high diastereoselectivity from three‐component reaction of L‐proline, isatins and chalcones and sequential reaction with dimethyl but‐2‐ynedioate or methyl propiolate in refluxing methanol. The ferrocenyl‐chalcones and dibenzylideneacetones were also successfully used in this one‐pot two‐step reaction to give novel ferrocenyl and styryl‐substituted spiro compounds. The reaction mechanism included domino [3+2] cycloadddtition reaction of azomethine ylide with chalcone and ring‐expansion reaction of in situ generated spiro[indoline‐3,3′‐pyrrolizine] with electron‐deficient alkynes. [ABSTRACT FROM AUTHOR]

A new type of azomethine ylides, which was in situ generated by the reaction of ethyl glycinate hydrochloride and dimethyl acetylenedicarboxylate, reacted with 3-phenacylideneoxindoline-2-ones in ethanol to give polysubstituted spiro[indoline-3,3′-pyrrolidines] in good yields. The biological activities of the various spiro[indoline-3,3′-pyrrolidines] obtained were investigated by in vitro evaluation against mouse breast cancer cells 4T1, mouse colon cancer cells CT26, human liver cancer cells HepG2 and human lung cancer cells A549 by MTT assay. The results demonstrated that eight compounds showed cytotoxicity towards HepG2 cells, and compound 2j showed promising cytotoxicity towards CT26 cells with an IC50 value of about 50 μg mL−1 in 24 h. [ABSTRACT FROM AUTHOR]

Triethylamine-promoted domino cyclodimerization reaction of 3-phenacylideneoxindolines with amino ester hydrochlorides in acetonitrile afforded substituted dispiro[indoline-3,1′-cyclopentane-3′,3″-indolines] in good yields. The relative configuration of the major diastereoisomers was determined by the X-ray diffraction analysis of three single crystal structures. [ABSTRACT FROM AUTHOR]

Under visible-light catalysis, a domino oxidative 1,3-dipolar cycloaddition reaction of alkyl 2-(3,4-dihydroisoquinolin-2-yl)acetate with 2-arylideneindane-1,3-diones has been developed that affords functionalized spiro[indene-2,1′-pyrrolo[2,1-a]isoquinoline]s in satisfactory yields and high diastereoselectivities. Depending on the electronic properties of the aryl group, similar reactions with tert-butyl 2-(3,4-dihydroisoquinolin-2-yl)acetate and 2-(3,4-dihydroisoquinolin-2(1 H)-yl)acetonitrile selectively gave spiro[indene-2,1′-pyrrolo[2,1-a]isoquinoline]s and 3-arylspiro[indene-2,2′-oxirane]-1,3-diones, respectively. [ABSTRACT FROM AUTHOR]

A cycloaddition reaction promoted by the Lewis acid BF3 ·OEt2 between 2-arylidene-1,3-indanediones and β-enamino esters, generated by the addition of arylamines to dimethyl acetylenedicarboxylate, gave densely substituted 1,4-diphenyl-4,5-dihydro-1 H-indeno[1,2- b]pyridines in satisfactory yields. When 2-isatylidene-1,3-indanediones were used under the same conditions, the one-pot reaction gave the corresponding spiro[indeno[1,2- b]pyridine-4,3′-indolines] in high yields. On the other hand, unusual 1,2-diphenyl-2,5-dihydro-1 H-indeno[1,2- b]pyridines were obtained in moderate to good yields through a four-component reaction. [ABSTRACT FROM AUTHOR]

The domino [2+2+2] cycloaddition reaction of α,β-unsaturated N-arylaldimines, dialkyl acetylenedicarboxylates, and arylidenemalononitriles in dry acetonitrile at room temperature afforded polysubstituted 6-styryl-1,4,5,6-tetrahydropyridines in good yields with various cis/trans-isomer ratios. The similar three-component reaction that contains ethyl aryl-idenecyanoacetates or arylidenepivaloylacetonitriles also resulted in polysubstituted 6-styryl-1,4,5,6-tetrahydropyridines, which can be separated into pure cis- and trans-isomers. The stereochemistry of the obtained polysubstituted 1,4,5,6-tetrahydropyridines is clearly elucidated on the basis of ¹H NMR spectroscopy and single-crystal structures. [ABSTRACT FROM AUTHOR]

Abstract: The cycloaddition reactions of a series of functionalized pyridinium salts, which were generated from reaction of pyridine with active alkyl halides such as p-nitrobenzyl bromide, N,N-diethyl chloroacetamide and phenacyl bromides with 3-phenacylideneoxindoles in the presence of triethylamine showed very interesting molecular diversities. A series of the functionalized spiro[cyclopropane-1,3′-indolines], and 3-furan-3(2H)-ylidene)indolin-2-ones were successfully prepared depending upon the structures of the pyridinium salts and reaction conditions. The regioselectivity and stereoselectivity of the reactions as well as reaction mechanisms were briefly discussed. [Copyright &y& Elsevier]

Deprotonation of pyridinium salts provides pyridinium ylides which undergo Michael addition/cyclization reaction with indole derivatives (I) to form spirocyclic compounds and furanylidene-oxindoles. [ABSTRACT FROM AUTHOR]

I 2 promoted cycloaddition reaction of 2-hydroxy-2-(indol-3-yl)-indane-1,3-diones with the in situ generated β -enamino esters, which were generated from the reaction of arylamines and dialkyl but-2-ynedioates, showed very interesting molecular diversity. In the presence of 30 % mmol iodine, the reaction in acetonitrile at 80 °C resulted in the novel spiro [indene-2,1′-pyrido [4,3- b ]indole] derivatives in good yields. On the other hand, in the presence of 80 % mmol iodine, the reaction in acetonitrile at 60 °C gave the ring-expanded benzo [5,6]pyrrolo [3′,2':3,4]cyclohepta [1,2- b ]indole derivatives in moderate to good yields. Additionally, the similar iodine-promoted reaction of 2-(indol-2-yl)diarylmethanols and β -enamino esters gave the unique 1,1,2-triphenyl-2,9-dihydropyrido [3,4- b ]indoles in satisfactory yields. A plausible domino annulation mechanism was rationally proposed for the formation of various polycyclic compounds. The reaction in acetonitrile at 80 °C in the presence of 30 % mmol iodine resulted in novel spiro [indene-2,1′-pyrido [4,3- b ]indole] derivatives in good yields. On the other hand, the reaction in acetonitrile at 60 °C in the presence of 80 % mmol iodine gave the ring-expanded opened benzo [5,6]pyrrolo [3′,2':3,4]cyclohepta [1,2- b ]indole derivatives in moderate to good yields. [Display omitted] [ABSTRACT FROM AUTHOR]

A straight forward synthetic protocol for spiro and fused chromenes has been developed by base promoted oxa -Michael/Mannich reaction of salicyl N -tosylimines and various cyclic dienophiles. 1,4-diazabicyclo[2.2.2]octane (DABCO) promoted [4 + 2] cycloaddition reaction of salicyl N -tosylimines and 3-methyleneoxindoles or 2-arylidene-1,3-indanediones in THF at room temperature afforded functionalized spiro[chromane-3,3′-indolines] or spiro[ chromane -3,2′- inden ]-1′,3′-diones in moderate to good yields and with high diastereoselectivity. On the other hands, the similar [4 + 2] cycloaddition of salicyl N -tosylimines and 5,6-unsubstituted 1,4-dihydropyridines resulted in tetrahydrochromeno[3,2- b ]pyridine derivatives in satisfactory yields. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: An efficient synthetic method for 1′-aryl-2′-(2-oxoindolin-3-yl)spiro[indoline-3,5′-pyrroline]-2,3′-diones was successfully developed via the one-pot domino reaction of arylamines, acetone, and isatins in acetic acid. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ formed 3-N-aryliminoisatin and isatylidene acetone. [Copyright &y& Elsevier]

The acid catalyzed domino reaction of β -nitrostyrenes with methyl 2-(benzo[ b ][1,4]thiazin-3-ylidene)acetate, which were previously prepared from the cyclization of 2-aminobenzenethiol and methyl 4-chloroacetoacetate, resulted in 2-arylbenzo[ b ]pyrrolo[1,2- d ][1,4]thiazine-3-carboxylates in high yields. Under same reaction conditions, the similar reaction with 3-nitrochromenes afforded corresponding benzo[ b ]chromeno[4′,3':4,5]pyrrolo[1,2- d ][1,4]thiazine derivatives in good yields. [ABSTRACT FROM AUTHOR]

The domino [2+2+2] cycloaddition reaction of α,β -unsaturated N -arylaldimines, dialkyl acetylenedicarboxylates and 2-arylidene-1,3-indanediones in dry methylene dichloride at room temperature afforded isomeric 2′-styryl-1,2′,3,4′-tetrahydro-1′ H -spiro[indene-2,3′-pyridines] in good yields. Under similar conditions, the reaction of α,β -unsaturated N -arylaldimines with two molecules of dialkyl acetylenedicarboxylates resulted in 1-aryl-6-styryl-1,6-dihydropyridine-2,3,4,5-tetracarboxylates. Additionally, the three-component reaction of α,β -unsaturated N -arylaldimines, dimethylacetylenedicarboxylate and benzoyl cyanide also gave isomeric 1,3-oxazine-4,5-dicarboxylates. [ABSTRACT FROM AUTHOR]

[Display omitted] In the presence of 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) as an oxidizer, the domino [3 + 2] cycloaddition reaction of aldohydrazones with 2-arylidene-1,3-indnaediones or 5-arylidene-1,3-dimethylbarbituric acids in acetonitrile at 80 °C afforded functionalized spiro[indene-2,4′-pyrazoles]-1,3-diones or 2,3,7,9-tetraazaspiro[4.5]dec-1-ene-6,8,10-triones in satisfactory yields. This reaction was believed to proceed with in situ generation of reactive 1,3-dipolar nitrilimine and its sequential 1,3-dipolar cycloaddition reaction with cyclic dipolarophiles. Thus, a new convenient synthetic method for the active dipolar nitrilimine was successfully developed. [ABSTRACT FROM AUTHOR]

An efficient protocol for the diastereoselective synthesis of the title compounds by 1,3-dipolar cycloaddition of N-phenacylbenzothiazolium and N-phenacylthiazolium bromides with several oxindoles is reported. [ABSTRACT FROM AUTHOR]

A facile synthesis of tricyclic skeleton of alkaloid 261C has been achieved by a double [3+2] cycloaddition of p -methoxypyridinium phenacyl bromide and maleimides with high diastereoselectivity. The initial Hammett analysis suggested that the most stable resonance form of pyridinium ylide is the one, the negative charge of which is widely dispersed in the pyridine ring. [ABSTRACT FROM AUTHOR]

An abstract on the domino cycloaddition reactions of N-benzylbenzimidazolium salts with oxoindolin and ylidene acetates is presented.

10α,20α-di(4-aminophenyl)calix[4]pyrroles were synthesized from the acid catalyzed cyclization of dialkyldipyrromethanes with p -nitroacetophenone and sequential hydrogenation of nitro group, which in turn reacted with several aromatic aldehydes and pyridinecarboxaldehydes as well as isocyanates to give a series of calix[4]pyrrole 10α,20α-disubstituted Schiff base and urea derivatives. The crystal structures of the newly-formed calix[4]pyrrole Schiff bases were successfully determined by X-ray diffraction. The complexing property of calix[4]pyrrole Schiff bases for transition metal ions was also investigated with UV–Vis spectroscopy. [ABSTRACT FROM AUTHOR]

A simple protocol is presented for the title Diels-Alder reaction that proceeds with high regio- and diastereoselectivity. [ABSTRACT FROM AUTHOR]

The title one-pot two-step process proceeds efficiently with ZnCl2 as promoter for the cyclization step. [ABSTRACT FROM AUTHOR]

Abstract: The cycloaddition reactions of 4-dimethylamino-1-alkoxycarbonylmethylpyridinium bromides with various 2-oxoindolin-3-ylidene derivatives in ethanol in the presence of triethylamine afforded the unprecedented dispirocyclopentanebisoxindole derivatives in good yields and in high diastereoselectivity. Under similar reaction conditions, the reactions of 1-alkoxycarbonylmethylpyridinium bromides with 3-phenacylideneoxindoles only resulted in 4-oxo-3-(2-oxoindolin-3-ylidene)-4-arylbutanoates. The stereochemistry of the complex spirooxindoles was established by 1H NMR data and single crystal structures. [Copyright &y& Elsevier]

Abstract: A sequential one-pot two-step tandem reaction for selective and efficient synthesis of pyrrolo[2,1-a]isoquinoline and its dihydro- and tetrahydro-derivatives has been developed. The tandem reactions of isoquinoline, α-halogenated methylene compounds, aromatic aldehydes, and cyanoacetamide firstly give tetrahydropyrrolo[2,1-a]isoquinolines as main products. The corresponding pyrrolo[2,1-a]isoquinolines and dihydropyrrolo[2,1-a]isoquinolines can be obtained directly by controlling oxidation with DDQ. The mechanism of this tandem reaction involved the 1,3-dipolar cycloaddition of isoquinolinium ylide as the key step. A unique elimination of the amido group preferring to the cyano group has been observed. [Copyright &y& Elsevier]

A graphical abstract of the article "Diastereoselective Synthesis of Spiro[indene-2,2′-pyrazolo[1,2-a]pyrazoles] and Spiro[indoline-3,2′-pyrazolo[1,2-a]pyrazoles] via 1,3-Dipolar Cycloaddition" is presented.

Depending on the molecular structure of the substrates and the reaction conditions, several functionalized spiro[indolinephenanthrene] and benzophenanthrodiazepine derivatives are prepared. [ABSTRACT FROM AUTHOR]

The domino cycloaddition of α,β-unsaturated N-aryl aldimines, acetylenedicarboxylates, and arylidenemalononitriles in dry MeCN at room temperature affords 6-styryl-l,4,5,6-tetrahydropyridines in good yields with various cis/trans ratios. [ABSTRACT FROM AUTHOR]

An uncatalyzed three-component reaction of 3-methylene oxindoles, α-amino acids, and dialkyl acetylenedicarboxylates proceeds with sequential generation of active α,β-enamino ester and azomethine ylide, followed by 1,3-dipolar cycloaddition reaction. [ABSTRACT FROM AUTHOR]

Spiro[indoline-3,3′-pyrrolizines] (IV), (VI) and (VIII) are obtained by normal 1,3-cycloaddition reaction of α-amino acids, isatins, and but-2-ynedioates. [ABSTRACT FROM AUTHOR]

The presence of the dimethylamino group in the pyridinium bromides leads to the unexpected formation of compounds (VII) and (IX), whereas pyridinium bromides (II) gives the corresponding products (III) and (IV). [ABSTRACT FROM AUTHOR]