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

Organic Letters, Journal Year: 2022, Volume and Issue: 24(3), P. 826 - 831

Published: Jan. 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.

Language: Английский

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Wound-Healing Material with Antibacterial and Antioxidant Functions, Constructed Using Keratin, Hyperbranched Polymers, and MnO₂

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(25), P. 29841 - 29853

Published: June 20, 2023

Wound healing, a global medical issue, poses substantial financial burden. Therefore, developing low-cost and highly efficacious wound-healing materials is essential. In this study, we prepared keratin–hyperbranched polymer hydrogel-M (KHBP-M), multifunctional composite gel, by mixing reduced keratin containing free sulfhydryl groups extracted from human hair waste, hyperbranched (HBP) with double bonds at the end, MnO2 nanoparticles using biological template method. Keratin has intrinsic properties, material both photothermal antibacterial reactive oxygen species (ROS)–scavenging abilities. KHBP-M showed effects against Gram-positive (Staphylococcus aureus) Gram-negative (Escherichia coli) bacteria. When exposed to irradiation (808 nm), killing ratio for S. aureus reached 99.99%, which especially suitable wound environments. A similar trend was noted E. coli. The hydrogel also excellent ROS-scavenging ability could resist oxidative stress in L929 cells. Furthermore, an animal model of infected wounds, treated near-infrared light had fastest rate, reaching 82.98% on day 15. Our study provides promising material, simple preparation methods, easy access sources, low cost involved.

Language: Английский

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

Organic Letters, Journal Year: 2021, Volume and Issue: 23(21), P. 8600 - 8605

Published: Oct. 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.

Language: Английский

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Recent Dearomatization Strategies of Benzofurans and Benzothiophenes

Asian Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 10(5), P. 932 - 948

Published: March 10, 2021

Abstract This review article discusses about the recent developments in area of strategies for dearomatization benzofurans and benzothiophenes (2010–2020). The readers can understand current state art this intriguingly important organic synthesis generation diversely functionalized molecules, polycyclic systems from highly abundant benzothiophenes. We hope that would help synthetic community design development new as well further growth novel rapidly growing research.

Language: 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, Journal Year: 2022, Volume and Issue: 87(9), P. 6025 - 6037

Published: April 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.

Language: Английский

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Progress in (Thio)urea‐ and Squaramide‐Based Brønsted Base Catalysts with Multiple H‐Bond Donors

European Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 26(7)

Published: Dec. 15, 2022

Abstract Thiourea‐ and squaramide‐based bifunctional base catalysts represent nowadays a powerful tool in the field of asymmetric catalysis have demonstrated very efficient for promoting wide variety transformations enantioselectively. New versions that incorporate one or various additional H‐bond donor site(s) catalyst structure been developed recently which led to more active (reduced loadings) selective catalysts. This review highlights pioneering ideas most recent contributions area with material organized according nature functionality. The advantages, current limitations perspectives these new multifunctional are discussed.

Language: 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, Journal Year: 2021, Volume and Issue: 8(22), P. 6330 - 6336

Published: Jan. 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.

Language: 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, Journal Year: 2020, Volume and Issue: 86(2), P. 1779 - 1788

Published: Dec. 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.

Language: 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, Journal Year: 2021, Volume and Issue: 363(12), P. 3115 - 3120

Published: April 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

Language: Английский

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Synthesis of Benzofuro[3,2-b]indol-3-one Derivatives via Dearomative (3 + 2) Cycloaddition of 2-Nitrobenzofurans and para-Quinamines

Molecules, Journal Year: 2024, Volume and Issue: 29(5), P. 1163 - 1163

Published: March 5, 2024

An efficient dearomative (3 + 2) cycloaddition of para-quinamines and 2-nitrobenzofurans has been developed. This reaction proceeds smoothly under mild conditions affords a series benzofuro[3,2-b]indol-3-one derivatives in good to excellent yields (up 98%) with perfect diastereoselectivities (all cases > 20:1 dr). The scale-up synthesis versatile derivatizations demonstrate the potential synthetic application protocol. A plausible mechanism is also proposed account for observed process. work represents first instance N-triggered 2-nitrobenzofurans.

Language: Английский

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