Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

A convenient synthetic procedure for the construction of novel dispirooxindole motifs was successfully developed by base-promoted three-component reaction of ammonium acetate, isatins and in situ-generated 3-isatyl-1,4-dicarbonyl compounds. The piperidine-promoted three-component reaction of ammonium acetate, isatins and the in situ-generated dimedone adducts of 3-ethoxycarbonylmethyleneoxindoles afforded mutlifunctionalized dispiro[indoline-3,2'-quinoline-3',3''-indoline] derivatives in good yields and with high diastereoselectivity. On the other hand, a similar reaction of the dimedone adducts of 3-phenacylideneoxindoles afforded unique dispiro[indoline-3,2'-pyrrole-3',3''-indoline] derivatives with a cyclohexanedione substituent. A plausible reaction mechanism is proposed to explain the formation of the different spirooxindoles.

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

An efficient tosylhydrazine-mediated conjugate reduction of 3-phenacylideneoxindole and sequential Michael/intramolecular aldol reaction is reported under base-catalyzed conditions towards the formation of densely substituted dispirocyclopentanebisoxindole derivatives. The reaction proceeded in a diastereoselective manner to afford four chiral stereocenters. The method also has advantages of wide substrate scope, readily available starting materials and operational simplicity through one pot reaction.

Effective and diastereoselective preparation of dispiro[cyclopent-3′-ene]bisoxindoles via novel [3 + 2] annulation of isoindigos and MBH carbonates

Efficient, one-step preparation of highly steric dispiro[cyclopent-3′-ene]bisoxindoles with two all-carbon quaternary spirocenters and three adjacent cycles in excellent yields and diastereoselectivities under mild conditions.

Stepwise cycloaddition reaction of N-phenacylbenzothiazolium bromides and nitroalkenes for tetrahydro-, dihydro- and benzo[d]pyrrolo[2,1-b]thiazoles

The triethylamine promoted stepwise 1,3-dipolar cycloaddition reaction of N-phenacylbenzothiazolium bromides with nitroalkenes in ethanol resulted in a mixture of two isomeric tetrahydrobenzo[d]pyrrolo[2,1-b]thiazoles with cis/trans/cis- and all-trans-configurations. More importantly, the corresponding dihydrobenzo[d]pyrrolo[2,1-b]thiazoles can be selectively prepared in refluxing ethanol and the benzo[d]pyrrolo[2,1-b]thiazoles can be obtained in satisfactory yields by sequential dehydrogenation with DDQ as oxidizer. On the other hand, the similar cycloaddition reaction of N-phenacylbenzothiazolium bromides with 1-methy-1-nitroalkenes in refluxing ethanol afforded benzo[d]pyrrolo[2,1-b]thiazoles with splitting out of nitro group. The stereochemistry of the spiro compounds was clearly elucidated on the basis of NMR spectra and sixteen single crystal structures.

Cyclodimerization of 3-phenacylideneoxindolines with amino esters for the synthesis of dispiro[indoline-3,1′-cyclopentane-3′,3″-indolines]

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.

Formation of diverse polycyclic spirooxindoles via three-component reaction of isoquinolinium salts, isatins and malononitrile

The triethylamine promoted three-component reaction of N-(4-nitrobenzyl), N-ethoxycarbonylmethylisoquinolinium bromide, isatins and malononitrile in ethanol afforded spiro[indoline-3,2′-pyrrolo[2,1-a]isoquinolines] in good yields and with high diastereoselectivity. The similar reaction of N-cyanomethylisoquinolinium chloride mainly gave complex indolo[2″,3″:2′,3′]pyrrolo[3′,4′:4,5]pyrrolo[2,1-a]isoquinoline derivatives. However, the three-component reaction of N-cyanomethylisoquinolinium chloride, isatins and ethyl cyanoacetate mainly resulted in functionalized spiro[indoline-3,8′-pyrido[2′,3′:4,5]pyrrolo[2,1-a]isoquinolines].

Diastereoselective synthesis of benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles via cycloaddition reaction of benzothiazolium salts with 3-nitrochromenes

Diastereospecific synthesis of benzo[d]chromeno[3′,4′:3,4]pyrrolo[2,1-b]thiazoles via cycloaddition reaction of benzothiazolium salts with 3-nitrochromenes.

A [3 + 2]–[4 + 2]–[3 + 2] cycloaddition sequence of isoquinolinium ylide

A unique [3 + 2]–[4 + 2]–[3 + 2] cycloaddition sequence of isoquinolinium ylide is investigated to afford polycyclic compounds with ten stereogenic centers.

Diastereoselective synthesis of dispiro[indoline-3,1′-cyclobutane-2′,3″-indolines] via visible light catalyzed cyclodimerization of 3-phenacylideneoxindoles

A simple synthetic protocol was developed for the efficient synthesis of functionalized dispiro[indoline-3,1′-cyclobutane-2′,3″-indolines] with high diastereoselectivity. The reaction proceeds by cyclodimerization reaction of 3-phenacylideneoxindoles in the presence of a catalytic amount of photosensitizer Ru(bpy

Indium chloride catalyzed three-component reaction for the synthesis of 2-((oxoindolin-3-yl)-4,5,6,7-tetrahydro-1H-indol-1-yl)benzamides

In the presence of indium chloride as a Lewis acid catalyst, the three-component reaction afforded functionalized 2-((oxoindolin-3-yl)-4,5,6,7-tetrahydro-1H-indol-1-yl)benzamides in satisfactory yields.

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

The 1,3-dipolar cycloaddition of cyclic azomethine imines with 2-arylideneindene-1,3-diones in refluxing acetonitrile afforded predominately cis-1,3-diaryl-substituted spiro[indene-2,2′-pyrazolo[1,2-a]pyrazole] derivatives in good yields.

Diastereoselective synthesis of spiro[benzo[d]pyrrolo[2,1-b]thiazole-3,3'-indolines] via cycloaddition reaction of N-phenacylbenzothiazolium bromides and 3-methyleneoxindoles

The domino cycloaddition reactions of N-phenacylbenzothiazolium bromides with 3-phenacylideneoxindoles or ethyl 2-(2-oxoindolin-3-ylidene)acetates in ethanol at room temperature in the presence of triethylamine as a base afforded functionalized spiro[benzo[d]pyrrolo[2,1-b]thiazole-3,3'-indolines] in good yields and with high diastereoselectivity. The similar reactions of N-phenacylthiazolium bromides with 3-phenacylideneoxindoles resulted in the corresponding functionalized spiro[indoline-3,7'-pyrrolo[2,1-b]thiazoles] in satisfactory yields and also with high diastereoselectivity.

Highly diastereoselective synthesis of imidazolidine-dispirooxindoles via three-component [3 + 2] cycloadditions of isatins, 2-(aminomethyl)pyridine and isatin-based imines

In the presence of Et₃N, the [3 + 2] cycloaddition of isatins, 2-(aminomethyl)pyridine and isatin-based imines proceeded readily, and furnished novel imidazolidine-dispirooxindoles in up to 84% yield with up to >99 : 1 diastereoselectivity.

Unprecedented formation of spiro[indoline-3,7′-pyrrolo[1,2-a]azepine] from multicomponent reaction of l-proline, isatin and but-2-ynedioate

Spiro[indoline-3,3′-pyrrolizines] and spiro[indoline-3,7′-pyrrolo[1,2-a]azepines] can be selectively produced from three-component reaction of α-amino acids, isatins and but-2-ynedioates.