Synthesis of Ketonylated Carbocycles via Excited‐State Copper‐Catalyzed Radical Carbo‐Aroylation of Unactivated Alkenes

ChemCatChem, Journal Year: 2022, Volume and Issue: 15(1)

Published: Dec. 13, 2022

Abstract Carbocycles are core skeletons in natural and synthetic organic compounds possessing a wide diversity of important biological activities. Herein, we report the development an excited‐state copper‐catalyzed radical carbo‐aroylation unactivated alkenes to synthesize ketonylated tetralins, di‐ tetrahydrophenanthrenes, cyclopentane derivatives. The reaction is operationally simple features mild conditions that tolerate broad range functional groups. Preliminary mechanistic studies suggest pathway beginning with photoexcitation Cu catalyst followed by single electron transfer (SET), aroylation alkenes, cyclization, re‐aromatization, affording desired carbocycles.

Language: Английский

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Flipping the Switch on Palladium-Catalyzed Carboiodination: Accessing Kinetic and Thermodynamic Products

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(10), P. 6562 - 6567

Published: April 28, 2023

A palladium-catalyzed epimerization reaction of stereogenic alkyl iodides is reported. This transformation involves use an air-stable precatalyst that efficiently epimerizes the C–I bond from exo to endo face [2.2.1] bicyclic compounds. Mechanistic experiments support stereoinversion via reversible formation generate antiproduct bearing iodide. Density functional theory studies were conducted a thermodynamically driven epimerization. Stoichiometric suggested irradiation isolable alkyl–Pd(II) complexes promoted reductive elimination, which could even be applied C–Br formation.

Language: Английский

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A S_NAr‐Active External Initiator that Enables Heterobifunctional Clickable Polythiophenes

Macromolecular Chemistry and Physics, Journal Year: 2023, Volume and Issue: 225(5)

Published: Oct. 20, 2023

Abstract Poly(3‐hexylthiophene) (P3HT) is a well‐studied conjugated polymer; however, the end‐group functionalization of these polymers limited by fundamental synthetic challenges. Generally, end‐capping agents are used to terminate Kumada catalyst transfer polycondensation (KCTP) install functional end‐groups at propagating chain end. In this work, it shown that P3HT can be prepared with novel S N Ar‐active external initiator, followed end capping afford heterobifunctional exhibit orthogonal chemical reactivity. This chemistry leveraged in sequential “click”‐type reactions ultimately achieve synthesis triblock copolymers. More specifically, new pentafluorophenyl initiator allows one append readily functionalized group initiating during synthesis. After reaching desired degree polymerization, an ethynyl incorporated polymer terminus using Grignard reagent. Critically, for both para‐fluoro thiol reactions, subset nucleophilic aromatic substitution (S Ar), and copper‐catalyzed alkyne‐azide cycloadditions (CuAAC). The efficacy design demonstrated assessing “click” different nonconjugated blocks either block.

Language: Английский

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Structurally Diverse Bench-Stable Nickel(0) Pre-Catalysts: A Practical Toolkit for In Situ Ligation Protocols

Published: Feb. 11, 2022

A flurry of recent research has centered on harnessing the power nickel catalysis in organic synthesis. These efforts have been bolstered by contemporaneous synthesis, characterization, and optimization well-defined (pre)catalysts with diverse structure reactivity. In this report, we present development ten different bench-stable, 18-electron, formally zero-valent nickel–olefin complexes that are shown to be competent pre-catalysts various reactions. Our investigation includes preparations novel, bench stable Ni(COD)(L) complexes, which L = quinone, cyclopentadienone, thiophene-S-oxide, fulvene. Characterization a battery techniques, including NMR, IR, single-crystal X-ray diffraction, cyclic voltammetry, thermogravimetric analysis, natural bond orbital analysis sheds light structure, bonding, properties these complexes. Kinetic profiling across series representative reactions reveals reactivity differences stem from nature ancillary ligand, underscoring complementary relationships between each pre-catalyst within toolkit.

Language: Английский

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Closing the Cycle as It Begins: Synthesis of ortho‐Iodobiaryls via Catellani Reaction

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 135(18)

Published: March 8, 2023

Abstract Despite the advances in field of carbon‐halogen bond formation, straightforward catalytic access to selectively functionalized iodoaryls remains a challenge. Here, we report one‐pot synthesis ortho ‐iodobiaryls from aryl iodides and bromides by palladium/norbornene catalysis. This new example Catellani reaction features initial cleavage C(sp 2 )−I bond, followed key formation palladacycle through C−H activation, oxidative addition an bromide ultimate restoration bond. A large variety valuable o has been synthesized satisfactory good yields their derivatization have described too. Beyond synthetic utility this transformation, DFT study provides insights on mechanism reductive elimination step, which is driven original transmetallation between palladium(II)‐halides complexes.

Language: Английский

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