Iridium‐Catalyzed Direct C4‐ and C7‐Selective Alkynylation of Indoles Using Sulfur‐Directing Groups

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(29), P. 9856 - 9860

Published: May 22, 2019

Abstract Indoles and their analogues have been one of the most ubiquitous heterocycles during past century, extensive studies conducted to establish practical synthetic methods for derivatives. In particular, selective functionalization poorly reactive benzenoid core over pyrrole ring has a great challenge. Reported herein is an iridium‐catalyzed direct alkynylation indole C4‐ C7‐positions with assistance sulfur directing groups. This transformation shows wide range functional‐group tolerance exceptional site selectivity. The group can be either easily removed or transformed after catalysis. utility alkyne fragment demonstrated by derivatization into structure natural alkaloids.

Language: Английский

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N-Ammonium Ylide Mediators for Electrochemical C–H Oxidation

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(20), P. 7859 - 7867

Published: May 13, 2021

The site-specific oxidation of strong C(sp3)-H bonds is uncontested utility in organic synthesis. From simplifying access to metabolites and late-stage diversification lead compounds truncating retrosynthetic plans, there a growing need for new reagents methods achieving such transformation both academic industrial circles. One main drawback current chemical the lack diversity with regard structure reactivity that prevents combinatorial approach rapid screening be employed. In regard, directed evolution still holds greatest promise complex C-H oxidations variety settings. Herein we present rationally designed platform provides step toward this challenge using N-ammonium ylides as electrochemically driven oxidants site-specific, chemoselective oxidation. By taking first-principles guided by computation, these mediators were identified rapidly expanded into library ubiquitous building blocks trivial synthesis techniques. ylide-based exhibits tunable selectivity often exclusive class can applied real-world problems agricultural pharmaceutical sectors.

Language: Английский

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Aerobic Oxidative Functionalization of Indoles

Advanced Synthesis & Catalysis, Journal Year: 2020, Volume and Issue: 362(18), P. 3795 - 3823

Published: May 18, 2020

Abstract The synthetic methodology for direct indole functionalizations is of great significance in chemistry and has been intensively investigated the last few decades. From perspective green chemistry, oxygen best choice as terminal oxidant molecular synthesis. Hence, aerobic oxidative functionalization indoles became a hot research topic decade. Numerous efficient protocols this field have discovered that enable facile transformations to related valuable compounds, which are summarized discussed detail review. magnified image

Language: Английский

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Electrochemical aromatic C–H hydroxylation in continuous flow

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: July 8, 2022

The direct hydroxylation of arene C-H bonds is a highly sought-after transformation but remains an unsolved challenge due to the difficulty in efficient and regioselective oxygenation high reactivity phenolic products leading overoxidation. Herein we report electrochemical arenes continuous flow for synthesis phenols. method characterized by broad scope (compatible with diverse electronic properties), mild conditions without any catalysts or chemical oxidants, excellent scalability as demonstrated production 1 mol (204 grams) one phenol products.

Language: Английский

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A Binuclear Cerium-Based Metal–Organic Framework as an Artificial Monooxygenase for the Saturated Hydrocarbon Aerobic Oxidation with High Efficiency and High Selectivity

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(13), P. 7821 - 7832

Published: June 17, 2022

Artificial enzymatic systems have emerged in the field of biomimetic catalysis by constructing specific catalytic centers enzymes. Inspired high activity natural monooxygenase for oxidation transformation, several binuclear Cu/Fe-based metal–organic frameworks (MOFs) been frequently used as catalysts, yet rarely reports MOFs with other metals nodes reported to date. In this work, ingenious decoration Ce–O–Ce moieties and anthraquinone groups good oxygen activation ability one framework, an MOF-supported artificial cerium was obtained highly selective inert C(sp3)–H bonds. The single-crystal structural study reveals that molecule-level modularity a moiety design MOF creates confined microenvironment offer ordered distribution dense substrate-accessible active sites throughout architecture. After photoexcitation, trigger ligand-to-metal charge-transfer (LMCT) event form bridge radical, which abstracts hydrogen atom from bond generate carbon-centered radical through typical transfer (HAT) process. These radicals rapidly combine reactive species (ROS) produced via energy (EnT) process alkyl peroxy intermediates, are easily trapped another unsaturated coordinated ions further facilitate their hydrolysis formation carbonyl products. This anthraquinone-functionalized framework containing resembling exhibits unique selectivity (>97%) activity, represent first example constructed different applying alkanes, expanding selection range metal monooxygenase. Taking advantage heterogeneity MOF, Ce–MOF recycled five times without decrease its possessed broader applicability substrate C–H bonds, providing blueprint designing new alkane oxidation.

Language: Английский

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