A rapid three-component MgI(2)-mediated synthesis of 3,3-pyrollidinyl spirooxindoles

Palladium-Catalyzed Annulative Coupling of Spirovinylcyclopropyl Oxindoles with p-Quinone Methides

Pd-catalyzed annulative coupling of spirovinylcyclopropyl oxindoles with p-quinone methides has been accomplished via cascade carbon-carbon bond formation to afford bis-spirooxindole scaffolds. The mild reaction conditions, diastereoselectivity, functional group diversity, post-synthetic transformations, and mechanistic studies using DFT calculations are the important practical features.

Selective C3-Allylation and Formal [3 + 2]-Annulation of Spiro-Aziridine Oxindoles: Synthesis of 5'-Substituted Spiro[pyrrolidine-3,3'-oxindoles] and Coerulescine

Brønsted acid- and/or Lewis acid-catalyzed selective C3-allylation and formal [3 + 2]-annulation of spiro-aziridine oxindoles with allylsilanes have been demonstrated to deliver direct access to 3-allyl-3-aminomethyl oxindoles and 5-silyl methyl spiro[pyrrolidine-3,3'-oxindoles], respectively. The acid-catalyzed methods do not provide any stereoselectivity when chiral spiroaziridines are used. However, the reaction of nonracemic sprioaziridines with allyl-Grignard reagent under catalyst-free conditions afforded 3-allyl-3-aminomethyl oxindoles with good stereoselectivity (ee up to 80%). The allylation protocol is utilized for the short synthesis of coerulescine and various 5'-substituted spiro[pyrrolidine-3,3'-oxindoles].

Bi-Catalyzed 1,2-Reactivity of Spirocyclopropyl Oxindoles with Dithianediol: Access to Spiroheterocycles

The efficient Bi-catalyzed 1,2-reactivity of spirocyclopropyl oxindoles has been disclosed with dithianediols as the sulfur surrogate to furnish spiroheterocycles at moderate temperature. The procedure provides a potential approach for the construction of spirotetrahydrothiophene scaffolds with functional group diversity. The catalytic 1,2-reactivity of cyclopropanes, mechanistic studies using density functional theory studies, diastereoselectivity, and additive-free mild conditions are the important practical features.

Lewis acid-catalyzed [3 + 2] annulations of oxindole based spirocyclic donor-acceptor cyclopropanes with ynamides

[3 + 2] annulations of oxindole based spirocyclic donor-acceptor cyclopropanes and ynamides catalyzed by copper triflate have been developed for the synthesis of biologically important spirocyclopenteneoxindoles. These reactions tolerated a wide scope of substrates and provided the desired products in good to high yields (up to 90%) with up to >40 : 1 diastereoselectivities under mild conditions.

Synthesis of 3-spirooxindole 3H-indoles through Rh(iii)-catalyzed [4 + 1] redox-neutral spirocyclization of N-aryl amidines with diazo oxindoles

Presented herein is a novel synthesis of 3-spirooxindole 3H-indoles via the coupling and spirocyclization of N-aryl amidines with diazo oxindoles.

Stereoselective synthesis and applications of spirocyclic oxindoles

This review summaries recent synthetic developments towards spirocyclic oxindoles and applications as valuable medicinal and synthetic targets.

Recent Advances in Stereoselective Ring Expansion of Spirocyclopropanes: Access to the Spirocyclic Compounds

Spirocyclopropane represents a privileged structural scaffold for accessing synthetic libraries of densely functionalized spirocarbo- and heterocyclic compounds. Due to the ubiquity of spirocyclic motifs as a potent pharmacophore in natural products and pharmaceuticals, recent years have witnessed significant advances in developing synthetic strategies that exploits carbon-carbon bond scission in spirocyclopropanes. This paper summarizes the recent developments in stereoselective ring expansion of spirocyclopropanes in diversity-oriented synthesis and highlights the synthetic as well as mechanistic rationale of those methodologies. This review also encompasses the applicability of the protocols in bioactive natural product syntheses.

Chameleon-Like Activating Nature of the Spirooxindole Group in Donor-Acceptor Cyclopropanes

The concept of a chameleon activating group is considered in the context of donor-acceptor cyclopropane chemistry. When spiro-conjugated with cyclopropane, oxindole can act as an acceptor or a donor depending on the electronic nature of vicinal substituents. This dichotomy is reflected in the alteration of chemoselectivity of spiro[oxindole-1,3'-cyclopropane] ring opening with nucleophiles.

Ni-Al Bimetallic Catalyzed Enantioselective Cycloaddition of Cyclopropyl Carboxamide with Alkyne

A Ni-Al bimetallic catalyzed enantioselective cycloaddition reaction of cyclopropyl carboxamides with alkynes has been developed. A series of cyclopentenyl carboxamides were obtained in up to 99% yield and 94% ee. The bifunctional-ligand-enabled bimetallic catalysis proved to be an efficient strategy for the C-C bond cleavage of unreactive cyclopropanes.

Lanthanide amide-catalyzed one-pot functionalization of isatins: synthesis of spiro[cyclopropan-1,3′-oxindoles] and 2-oxoindolin-3-yl phosphates

A lanthanide-catalyzed one-pot reaction using readily accessible substrates was developed affording spiro[cyclopropan-1,3′-oxindoles] in good yields and with high stereoselectivity.

Organoiodine reagent-promoted intermolecular oxidative amination: synthesis of cyclopropyl spirooxindoles

An organoiodine-promoted intramolecular direct oxidative C(sp²)–N cross-coupling reaction was developed for the preparation of cyclopropyl spirooxindoles from readily available secondary cyclopropyl carboxamides.

Three structures of dispirooxindole derivatives generatedin situthrough a three-component one-pot strategy with complete regio- and stereoselectivity

The challenging molecular architecture of spirooxindoles is appealing to chemists because it evokes novel synthetic strategies that address configurational demands and provides platforms for further reaction development. The [3+2] cycloaddition of the carbonyl ylide with arylideneoxindoleviaa five-membered cyclic transition state gave a novel class of dispirooxindole derivatives, namelytert-butyl 4′-(4-bromophenyl)-1′′-methyl-2,2′′-dioxo-5′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-1-carboxylate, C36H31BrN2O, (Ia), 5′-(4-bromophenyl)-1,1′′-dimethyl-4′-phenyl-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-2,2′′-dione, C32H25BrN2O3, (Ib), andtert-butyl 1′′-methyl-2,2′′-dioxo-4′-phenyl-5′-(p-tolyl)-4′,5′-dihydrodispiro[indoline-3,2′-furan-3′,3′′-indoline]-1-carboxylate, C37H34N2O5, (Ic). Crystal structure analyses of these dispirooxindoles revealed the formation of two diastereoisomers selectively and confirmed their relative stereochemistry (SSSRandRRRS). In all three structures, intramolecular C—H...O and π–π interactions between oxindole and dihydrofuran rings are the key factors governing the regio- and stereoselectivity, and in the absence of conventional hydrogen bonds, their crystal packings are strengthened by intermolecular C—H...π interactions.

Catalytic asymmetric synthesis of polysubstituted spirocyclopropyl oxindoles: organocatalysis versus transition metal catalysis

Recent progress in catalytic asymmetric synthesis of spirocyclopropyl oxindoles via organocatalysis and transition metal catalysis are summarized and discussed.

Copper(i)/Lewis acid triggered ring-opening coupling reaction of cyclopropenes with nitriles

A ring-opening coupling reaction of D–A cyclopropenes and nitriles is described for the facile synthesis of γ-amino ketones.

1,3-Carbon D–A strategy for [3 + 2] cycloadditions/annulations with imines: synthesis of functionalized pyrrolidines and related alkaloids

[3 + 2] Cycloaddition/annulation: this article summarize the recent developments in synthesis of pyrrolidines and related alkaloids through complementary [3 + 2] cycloaddition/annulation of 1,3-carbon D–A precursors with imines.

Cu(II)-promoted transformations of α-thienylcarbinols into spirothienooxindoles: regioselective halogenation of dienyl sulfethers containing electron-rich aryl rings

Under the promotion of Cu(II) salts, the α-thienylcarbinols with an N-phenyl carbonyl group at the other α-position are converted into three different ranges of spirothienooxindoles involving dearomatizing Friedel-Crafts reaction. In addition, the unprecedented regioselective CuX(2)-mediated C-H functionalization/halogenation of dienyl sulfether containing electron-rich aryl rings is presented.

Highly stereoselective Brønsted acid catalyzed synthesis of spirooxindole pyrans

A Brønsted acid-catalyzed Prins-type cyclization sequence to construct spirooxindole pyrans in high yields and excellent diastereoselectivity has been developed. The combination of a β-hydroxy dioxinone fragment and isatin dimethyl acetal generate oxa-spirooxindoles efficiently. These compounds are diversifiable scaffolds that tap into the rich chemistry of dioxinones.