Catalytic Asymmetric Dearomative 1,3-Dipolar Cycloaddition of 2-Nitrobenzothiophenes and Isatin-Derived Azomethine Ylides

Organic Letters, Год журнала: 2021, Номер 23(21), С. 8600 - 8605

Опубликована: Окт. 21, 2021

An enantioselective dearomative 1,3-dipolar cycloaddition of 2-nitrobenzothiophenes and isatin-derived azomethine ylides with a bifunctional hydrogen-bonding thiourea catalyst was established, giving polyheterocyclic compounds in excellent results (up to 99% yield, >20:1 dr for all cases up ee). The enantioselectivity could be reversed by the squaramide containing same chiral source as catalyst. DFT calculations revealed origin observed stereochemistry reversal enantioselectivity.

Язык: Английский

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Ag-Catalyzed Asymmetric Interrupted Barton–Zard Reaction Enabling the Enantioselective Dearomatization of 2- and 3-Nitroindoles

Organic Letters, Год журнала: 2022, Номер 24(3), С. 826 - 831

Опубликована: Янв. 14, 2022

We disclose a Ag-catalyzed asymmetric interrupted Barton–Zard reaction of α-aryl-substituted isocyanoacetates with 2- and 3-nitroindoles, which enables the dearomatization nitroindoles hence offers rapid access to an array optically active tetrahydropyrrolo[3,4-b]indole derivatives bearing three contiguous stereogenic centers, including two tetrasubstituted chiral carbon atoms pretty outcomes (up 99% yield, 91:9 dr, 96% ee). The synthetic potential protocol was showcased by gram-scale versatile transformations product.

Язык: Английский

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Dearomatization of 3-Nitroindoles Enabled Using Palladium-Catalyzed Decarboxylative [4 + 2] Cycloaddition of 2-Alkylidenetrimethylene Carbonates

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(9), С. 6025 - 6037

Опубликована: Апрель 18, 2022

A dearomatization process of 3-nitroindoles enabled using palladium-catalyzed decarboxylative [4 + 2] cycloaddition either 2-alkylidenetrimethylene carbonates or 2-(hydroxymethyl)-3-arylallyl has been developed, affording a wide range indoline-fused tetrahydropyrans in good yields with excellent diastereoselectivities. This reaction features substrate scope and mild conditions represents the first example application π-allyl palladium 1,4-[O,C]-dipole species for dearomative electron-deficient heteroarenes.

Язык: Английский

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Catalytic asymmetric dearomative [4 + 2] annulation of 2-nitrobenzofurans and 5H-thiazol-4-ones: stereoselective construction of dihydrobenzofuran-bridged polycyclic skeletons

Organic Chemistry Frontiers, Год журнала: 2021, Номер 8(22), С. 6330 - 6336

Опубликована: Янв. 1, 2021

An organocatalytic asymmetric dearomative [4 + 2] annulation of 2-nitrobenzofurans and 5 H -thiazol-4-ones is developed for the construction dihydrobenzofuran-bridged polycyclic skeletons with good results.

Язык: Английский

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Enantioselective [4 + 2] Cycloaddition/Cyclization Cascade Reaction and Total Synthesis of cis-Bis(cyclotryptamine) Alkaloids

Organic Letters, Год журнала: 2021, Номер 23(5), С. 1856 - 1861

Опубликована: Фев. 23, 2021

The asymmetric catalytic synthesis of 3-cyclotryptamine substituted oxindoles through formal [4 + 2] cycloaddition/cyclization cascade is described. A wide range cyclotryptamine derivatives were obtained in enantioenriched form under mild reaction conditions and found to have potential anticancer activity. strategy enables ready assembly subunits at the C3a–C3a′ positions with two quaternary stereogenic centers cis-selectivity, leading concise optically active cis-bis(hexahydropyrroloindole) others alkaloid family.

Язык: Английский

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Copper-Catalyzed Decarboxylative [3 + 2] Annulation of Ethynylethylene Carbonates with Azlactones: Access to γ-Butyrolactones Bearing Two Vicinal Quaternary Carbon Centers

The Journal of Organic Chemistry, Год журнала: 2020, Номер 86(2), С. 1779 - 1788

Опубликована: Дек. 30, 2020

An efficient decarboxylative [3 + 2] annulation reaction of ethynylethylene carbonates and azlactones has been developed with a copper salt as catalyst. This practical methodology gives access to diverse library γ-butyrolactones bearing α,β-two vicinal quaternary carbon centers in good high yields levels diastereoselectivities (up 98% yield, >95:5 dr). Preliminary trials on enantioselective variant chiral PyBox ligand provided products up 71% ee. synthetic method features mild conditions, broad functional group tolerance, large-scale synthesis, versatile transformation. A plausible catalytic cycle for the protocol is proposed based previous related studies our experimental observations.

Язык: Английский

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Bifunctinoal Phosphonium Salt‐Catalyzed Asymmetric Cyclodearomatization of 2‐Nitroindoles and 2‐Nitrobenzofurans for Constructing CF₃‐Containing Spiro‐Polycycles

Advanced Synthesis & Catalysis, Год журнала: 2021, Номер 363(12), С. 3115 - 3120

Опубликована: Апрель 13, 2021

Abstract An efficient enantioselective dearomative cycloaddition reaction between either 2‐nitroindoles or 2‐nitrobenzofurans and N ‐2,2,2‐trifluoroethylisatin ketimines by dipeptided phosphonium salt catalysis is firstly established. This protocol provides a new facile synthetic approach to create variety of CF 3 ‐containing polycyclic spirooxindole derivatives under mild conditions with high yields in excellent diastereo‐ enantioselectivities (all >20:1 dr , up 95% ee). magnified image

Язык: Английский

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Organocatalyzed asymmetric dearomative 1,3‐dipolar cycloaddition of 2‐nitrobenzofurans and N‐2,2,2‐trifluoroethylisatin ketimines

Chirality, Год журнала: 2022, Номер 34(7), С. 1019 - 1034

Опубликована: Май 6, 2022

Abstract A readily available chiral cyclohexanediamine‐derived bifunctional tertiary amine‐squaramide catalyst is more effective for the asymmetric dearomative 1,3‐dipolar cycloaddition of 2‐nitrobenzofurans and N ‐2,2,2‐trifluoroethylisatin ketimines. range structurally diverse spiro‐fused polyheterocyclic compounds containing oxindole, pyrrolidine, hydrobenzofuran motifs were smoothly obtained in excellent results (up to 99% yield, >20:1 dr all cases up ee). This method features high efficiency, mild reaction conditions, exquisite induction, wide functional group tolerance, great potential scale‐up synthesis, attractive product diversification.

Язык: Английский

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Dinuclear Zinc Catalyzed Enantioselective Dearomatization [3+2] Annulation of 2‐Nitrobenzofurans and 2‐Nitrobenzothiophenes

Chemistry - A European Journal, Год журнала: 2021, Номер 28(2)

Опубликована: Окт. 29, 2021

The application of dinuclear zinc catalysts in a dearomatization reaction has been developed. Catalytic asymmetric [3+2] annulations 2-nitrobenzofurans or 2-nitrobenzothiophenes with CF3 -containing N-unprotected isatin-derived azomethine ylides catalyzed by are realized excellent diastereomer ratios (dr) >20 : 1 and enantiomeric excess (ee) up to 99 %. This protocol provides practical, straightforward access structurally diverse pyrrolidinyl spirooxindoles containing 2,3-fused-dihydrobenzofuran (or dihydrobenzothiphene) moiety, four contiguous stereocenters. Reactions can be performed on gram scale. absolute configuration products is confirmed X-ray single crystal structure analysis, possible mechanism proposed.

Язык: Английский

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Advances in chromone-based reactants in the ring opening and skeletal reconstruction reaction: access to skeletally diverse salicyloylbenzene/heterocycle derivatives

Organic & Biomolecular Chemistry, Год журнала: 2022, Номер 20(23), С. 4681 - 4698

Опубликована: Янв. 1, 2022

Salicyloylbenzene/heterocycles are privileged scaffolds found in many natural products and bioactive molecules. Numerous useful approaches for the preparation of these have been developed recent years. Among approaches, chromone-based reactants demonstrated their importance synthesis salicyloylbenzene/heterocycle with structural complexity potential biological appeal. In this review, advances salicyloylbenzene/heterocycles summarized discussed according to which could be achieved one step via ring-opening skeletal reconstruction reactions. Both mechanisms applications corresponding organic medicinal chemistry also described.

Язык: Английский

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