Controlling Reactivity and Selectivity in the Nondirected C–H Activation of Arenes with Palladium

Accounts of Chemical Research, Год журнала: 2023, Номер 56(18), С. 2459 - 2472

Опубликована: Авг. 24, 2023

ConspectusAromatic structures are widespread motifs throughout organic chemistry, and C-H activation has been recognized as a major tool for enabling their sustainable efficient functionalization. Through activation, arenes can be modified without the need prefunctionalization, leading to inherent atom- step-economic advantages over traditional methods. However, development of synthetically useful methods, several hurdles have overcome. The strength bonds necessitates sufficiently reactive catalysts, while presence multiple within substrate poses challenges in terms site-selectivity. Traditionally these addressed by control. By attaching different directing groups (DGs), reactivity respective arene was significantly enhanced DG guided metal close proximity specific bonds, resulting high introduction removal add additional steps synthetic sequence, scope reaction is limited class. complementary nondirected methods that applied broad range necessity carry functional group coordinates Pd (referred simple arenes) therefore highly desirable. intrinsically lower such substrates absence selectivity-determining pose significant solved only catalysts. Consequently, field especially with respect Pd-catalyzed remained comparatively underdeveloped when we initiated our research program 2017. At time, state-of-the-art required used large excess, precluding its use late-stage Since organopalladium species among most versatile intermediates, realized developing system, which effectively selectively activate limiting reagent, would powerful chemistry. This account summarizes groups' toward application catalytic systems offering this desired focuses explicitly on functionalization reactions arenes, where employed reagent. After an state before 2017 associated challenges, experimental mechanistic details about first arene-limited, palladium will discussed. enabled identification combination two ligands, N-heterocycle amino acid-derived ligand. Afterward discuss expansion dual-ligand approach further arene-limited transformations. Finally, describe methodologies originated from observations made during studies, namely, deuteration selective olefination method uses noncovalent interactions induce meta selectivity.

Язык: Английский

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Advancing Heterogeneous Organic Synthesis With Coordination Chemistry‐Empowered Single‐Atom Catalysts

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 18, 2024

Abstract For traditional metal complexes, intricate chemistry is required to acquire appropriate ligands for controlling the electron and steric hindrance of active centers. Comparatively, preparation single‐atom catalysts much easier with more straightforward effective accesses arrangement control The presence coordination atoms or neighboring functional on supports' surface ensures stability single‐atoms their interactions individual substantially regulate performance Therefore, collaborative interaction between surrounding environment enhances initiation reaction substrates formation transformation crucial intermediate compounds, which imparts significant catalytic efficacy, rendering them a valuable framework investigating correlation structure activity, as well mechanism in organic reactions. Herein, comprehensive overviews both homogeneous complexes reactions are provided. Additionally, reflective conjectures about advancement synthesis also proposed present reference later development.

Язык: Английский

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Mn(I)-Catalyzed Preferential Electrophilic C3-Maleimidation in Quinoxaline Leading to Spirocyclization and Dehydrogenation of Succinimides

Organic Letters, Год журнала: 2023, Номер 25(20), С. 3806 - 3811

Опубликована: Май 17, 2023

A Mn(I)-catalyzed site-selective nondirected C3-maleimidation of quinoxaline is established. Herein, the electrophilic C3-metalation precedes over o-directed strategy to access diversely substituted quinoxaline-appended succinimides. The products undergo PIFA-promoted C(sp2)-C(sp3) spirocyclization via π-electrons drifting from aryls and Selectfluor-mediated dehydrogenation succinimide at room temperature.

Язык: Английский

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Palladium(II)‐Catalyzed Nondirected Late‐Stage C(sp²)−H Deuteration of Heteroarenes Enabled Through a Multi‐Substrate Screening Approach

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(27)

Опубликована: Март 21, 2024

The importance of deuterium labelling in a variety applications, ranging from mechanistic studies to drug-discovery, has spurred immense interest the development new methods for its efficient incorporation organic, and especially bioactive molecules. five-membered heteroarenes at center this work are ubiquitous motifs molecules these compounds therefore highly desirable. However, profound differences chemical properties encountered between different hamper single set broadly applicable reaction conditions, often necessitating separate optimization campaign given type heteroarene. In study we describe use multi-substrate screening approach identify optimal conditions classes minimal number reactions. Using approach, four sets complementary derived our dual ligand-based palladium catalysts nondirected C(sp

Язык: Английский

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Extended π-conjugated systems by external ligand-assisted C−H olefination of heterocycles: Facile access to single-molecular white-light-emitting and NIR fluorescence materials

Chinese Chemical Letters, Год журнала: 2024, Номер unknown, С. 110113 - 110113

Опубликована: Июнь 1, 2024

Язык: Английский

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Orthogonal Olefination with Organogermanes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(43)

Опубликована: Сен. 12, 2023

Reported herein is a fully orthogonal olefination, which involves the site- and E-selective coupling of aryl germanes with alkenes, tolerating otherwise widely employed handles such as aromatic (pseudo)halogens (C-I, C-Br, C-Cl, C-F, C-OTf, C-OSO2 F), silanes boronic acid derivatives well alternative functionalities. This unprecedented [Ge]-based oxidative Heck proceeds at room temperature high speed (10 min to 2 hours) operational simplicity owing its base-free air-tolerant features.

Язык: Английский

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Palladium(II) NCS‐Pincer Complexes Mediated Regioselective Cross Dehydrogenative Alkenation of 2‐Arylthiophenes

ChemCatChem, Год журнала: 2024, Номер 16(15)

Опубликована: Март 18, 2024

Abstract In this report, we have synthesized two new NCS pincer ligands by the Schiff base reaction of 3‐((phenylthio)methoxy)benzaldehyde ( P ) with alkyl amines t butylamine L1 and 1‐adamantylamine L2 )). The palladium complexes butylamine= C1 1‐adamantylamine= C2 these were their PdCl 2 (CH 3 CN) precursor. newly characterized using various analytical spectroscopic techniques such as 1 H, 13 C{ H} Nuclear Magnetic Resonance (NMR), Ultraviolet–visible (UV‐Visible), Fourier Transform Infrared (FTIR) Spectroscopy, High‐Resolution Mass Spectrometry (HRMS). structure ligand its coordination mode precursor studied help single‐crystal X‐ray diffraction. showed distorted square planar geometry around center. used catalysts for regioselective cross‐dehydrogenative alkenation 2‐arylthiophene derivatives. complex , where sterically bulky adamantyl is part side arm a higher yield reaction. Only 2.5 mol% catalyst loading was sufficient to achieve 74–95 % yields desired products excellent functional group tolerance under mild conditions. poisoning experiments (PPh Hg) homogeneous nature catalytic process. plausible mechanism proposed based on control time‐dependent HRMS studies.

Язык: Английский

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Advances in Pyridine C – H Functionalizations: Beyond C2 Selectivity

Chemistry - A European Journal, Год журнала: 2024, Номер 31(2)

Опубликована: Ноя. 28, 2024

The pyridine core is a crucial component in numerous FDA-approved drugs and Environmental Protection Agency (EPA) regulated agrochemicals. It also plays significant role ligands for transition metals, alkaloids, catalysts, various organic materials with diverse properties, making it one of the most important structural frameworks. However, despite its significance, direct selective functionalization still relatively underdeveloped due to electron-deficient nature strong coordinating ability nitrogen. Among variety synthetic transformation, C-H bond straightforward atom economical approach it's advantageous late-stage containing drugs. In recent years, innovative strategies regioselective pyridines azines have emerged, offering benefits such as high regioselectivity, mild conditions, enabling transformations that were challenging traditional methods. This review emphasizes latest advancements meta para-C-H through approaches, including phosphonium salts, photocatalytic methods, temporary de-aromatization, Minisci-type reactions, metal-catalyzed activation techniques. We discuss advantages limitations these current methods aim inspire further progress this field.

Язык: Английский

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Dual ligands relay-promoted transformation of unstrained ketones to polyfluoroarenes and nitriles

Science China Chemistry, Год журнала: 2023, Номер 66(7), С. 2037 - 2045

Опубликована: Июнь 20, 2023

Язык: Английский

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Direct C3‐H Alkylation and Alkenylation of Quinolines with Enones

Angewandte Chemie International Edition, Год журнала: 2024, Номер 64(1)

Опубликована: Сен. 19, 2024

Conversion of quinoline C-H bonds into C-C is essential for obtaining the enormous array derivatives required pharmaceutical and agrochemical development. Despite over a century synthetic efforts, direct alkylation alkenylation at C3-H positions in wide precursors remain predominantly challenging elusive. This report outlines first successful reactions, exhibiting exceptional regio- stereoselectivity, all achieved under redox-neutral transition-metal-free conditions. The method involves three-step, one-pot or two-pot sequence, including 1,4-dearomative addition, functionalization C3, elimination transalkylation to produce 3-alkylated/alkenylated quinolines. presence carbonyl group these products allows further manipulations, enabling production cyanides, amides, amines, simple alkyl derivatives.

Язык: Английский

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