Spiroindoles as Intermediates/Products in Transition Metal-Catalyzed Dearomatization of Indoles

ACS Catalysis, Год журнала: 2023, Номер 13(14), С. 9442 - 9475

Опубликована: Июль 3, 2023

Spirocyclic indole derivatives are fascinating tridimensional molecular scaffolds from both a synthetic and biological point of view. Among the many strategies developed to access these structures, transition metal catalysis has recently led impressive advances, especially relying on unique reactivity dearomatized spirocyclic intermediates. These species can indeed evolve toward or nonspirocyclic products through rearomatization-driven processes, which at same time highly challenging control but also source large structural diversity. This review highlights most prominent methods past decade that involve spirocyclization tethered functional group may be activated by metal, leading rearomatized products. The discussion is particularly focused spiroindoleninium intermediate complex mechanistic features regarding its evolution, dependent catalytic systems.

Язык: Английский

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Advances in gold catalyzed synthesis of quinoid heteroaryls

RSC Advances, Год журнала: 2024, Номер 14(29), С. 21047 - 21064

Опубликована: Янв. 1, 2024

Synthesis of quinoid heteroaryls via gold-catalyzed cascade protocols: recent advances and methodologies.

Язык: Английский

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Dearomative (3 + 2) Cycloadditions of 3-Nitroheteroarenes with Allenyl Sulfones Mediated by Ion Pair Organocatalysis

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Фев. 8, 2025

We report the first example of dearomative (3 + 2) cycloadditions 3-nitro(aza)-indole, -benzofuran, and -benzothiophene derivatives in presence allenyl sulfones, using sulfinate ammonium ion pairs as organocatalytic promoters. The methodology provides a new, facile, efficient protocol for synthesis functionalized 2,3-fused cyclopentannulated indolines dihydrobenzofurans.

Язык: Английский

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Chiral Phosphathiahelicenes: Improved Synthetic Approach and Uses in Enantioselective Gold(I)-Catalyzed [2 + 2] Cycloadditions of N-Homoallenyl Tryptamines

ACS Catalysis, Год журнала: 2020, Номер 10(15), С. 8141 - 8148

Опубликована: Июнь 23, 2020

A chiral phosphathiahelicene scaffold displaying a phosphole and thiophene unit as the terminal rings of helical sequence has been synthesized characterized by spectroscopic methods X-ray diffraction studies. The phosphine oxides (HelPhos-V oxides) have obtained following robust scalable synthetic approach, based on nickel-promoted alkyne cyclotrimerization reaction. Then, late-stage functionalization carried out via bromination/palladium coupling reaction sequence. HelPhos-V gold(I) complexes used catalysts in unprecedented enantioselective [2 + 2] cyclization N-homoallenyl tryptamine derivatives, to afford indolenine-fused cyclobutanes good isolated yields, with enantiomeric excesses up 93%.

Язык: Английский

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Synthesis of CF₃-Containing Spirocyclic Indolines via a Red-Light-Mediated Trifluoromethylation/Dearomatization Cascade

The Journal of Organic Chemistry, Год журнала: 2021, Номер 86(15), С. 10640 - 10653

Опубликована: Июль 13, 2021

A red-light-mediated nPr-DMQA+-catalyzed cascade intramolecular trifluoromethylation and dearomatization of indole derivatives with Umemoto's reagent has been developed. This protocol provides a facile efficient approach for the construction functionalized potentially biologically important CF3-containing 3,3-spirocyclic indolines moderate to high yields excellent diastereoselectivities under mild conditions. The success multiple gram-scale (1 10 g) experiments further highlights robustness practicality this merit employment red light. Mechanistic studies support formation crucial CF3 radical species dearomatized benzyl carbocation intermediate.

Язык: Английский

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Synthesis of Cyclopenta[b]indoles via Sc(III)-Catalyzed Annulation of Vinyl Diazoacetates with Indole-Derived Unsaturated Imines

Organic Letters, Год журнала: 2023, Номер 25(18), С. 3184 - 3189

Опубликована: Май 1, 2023

A Lewis acid Sc(OTf)3-catalyzed annulation reaction of vinyl diazoacetates with in situ formed α,β-unsaturated imines for the preparation indole-fused tricyclic rings has been reported. This strategy involves a sequential addition/rebound addition process and an dedinitrogenation. protocol features low-cost catalysts, mild conditions, facilely prepared substrates.

Язык: Английский

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Gold-Catalyzed Spirocyclization Reactions of N-Propargyl Tryptamines and Tryptophans in Aqueous Media

Organic Letters, Год журнала: 2020, Номер 22(11), С. 4344 - 4349

Опубликована: Май 12, 2020

N-Propargyl tryptamine and tryptophan derivatives that are readily available from both synthetic biocatalytic approaches undergo gold-catalyzed dearomative cyclizations in aqueous media to the corresponding spirocyclic derivatives. In addition efficiency of method, operating affords a selective entry C2-unsubstituted spiroindolenines have long remained unattainable by Au(I) catalysis. Moderate excellent yields desired products bearing various substituents were obtained.

Язык: Английский

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Silver-Catalyzed, Chemo- and Enantioselective Intramolecular Dearomatization of Indoles to Access Sterically Congested Azaspiro Frameworks

The Journal of Organic Chemistry, Год журнала: 2020, Номер 85(16), С. 10934 - 10950

Опубликована: Июль 21, 2020

An asymmetric dearomatization of indoles bearing α-diazoacetamide functionalities was developed for synthesizing high-value spiro scaffolds. A silver phosphate chemoselectively catalyzed the sterically challenging dearomatization, whereas more typically used metal catalysts carbene transfer reactions, such as a rhodium complex, were not effective and instead resulted in Büchner ring expansion or cyclopropanation. Mechanistic studies indicated that spirocyclization occurred through silver-assisted asynchronous concerted process via silver–carbene intermediate. Analyses based on natural bond orbital population distortion/interaction model degree C–Ag mutual interaction is crucial achieving high level enantiocontrol. In addition, an oxidative disconnection C(sp3)–C(sp2) product provided unconventional access to corresponding chiral spirooxindole.

Язык: Английский

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Synthesis of Spirocyclic 1‐Pyrrolines from Nitrones and Arynes through a Dearomative [3,3′]‐Sigmatropic Rearrangement

Angewandte Chemie International Edition, Год журнала: 2020, Номер 59(35), С. 15244 - 15248

Опубликована: Май 6, 2020

A dearomative [3,3']-sigmatropic rearrangement that converts N-alkenylbenzisoxazolines into spirocyclic pyrroline cyclohexadienones has been developed by using the dipolar cycloaddition of an N-alkenylnitrone and aryne to access these unusual transient precursors. This cascade reaction affords pyrrolines are inaccessible through cycloadditions exocyclic cyclohexenones provides a fundamentally new approach novel pyrrolidine motifs common scaffolds in biologically-active molecules. Diastereoselective functionalization processes have also explored demonstrate divergent synthetic utility unsaturated products.

Язык: Английский

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Selectivity Control in Gold-Catalyzed Hydroarylation of Alkynes with Indoles: Application to Unsymmetrical Bis(indolyl)methanes

Organic Letters, Год журнала: 2020, Номер 22(17), С. 6977 - 6981

Опубликована: Авг. 26, 2020

Gold-catalyzed hydroarylation of unactivated alkynes with indoles have previously been reported to proceed double indole addition produce symmetrical bis(indolyl)methanes (BIMs). We demonstrate for the first time that selectivity gold-catalyzed reaction can be fully switched allow isolation vinylindole products instead. Furthermore, this selective utilized synthesize more difficult access unsymmetrical BIMs from readily available starting materials.

Язык: Английский

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