Transition‐Metal‐Catalyzed Annulations Involving the Activation of C(sp³)−H Bonds

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(6)

Published: Oct. 26, 2021

The selective functionalization of C(sp

Language: Английский

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Tandem Reactions involving 1,4‐Palladium Migrations

Chemistry - An Asian Journal, Journal Year: 2022, Volume and Issue: 17(15)

Published: June 6, 2022

Abstract Transition‐metal‐catalyzed tandem reactions have become a mainstay in organic chemistry owing to their high atom‐ and step‐economies. Metal‐migration‐based allow the engagement of simple starting materials for incorporating functional groups into certain positions constructing complex scaffolds, which provide novel means that are complementary traditional cross‐coupling or C−H activation processes. In light broad utility 1,4‐Pd migration reaction, this paper reviews its progress past two decades, summarizing process classifying it based on insertion, elimination, transmetalation, bond activation. Special emphasis is placed driving force Pd different mechanisms. Moreover, review also attempts summarize common strategies improving regio‐ site‐selectivities process.

Language: Английский

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Palladium-Catalyzed [3 + 2] Annulation of Aromatic Amides with Maleimides through Dual C–H Activation

Organic Letters, Journal Year: 2023, Volume and Issue: 25(13), P. 2190 - 2195

Published: March 26, 2023

A palladium-catalyzed [3 + 2] annulation of substituted aromatic amides with maleimides providing tricyclic heterocyclic molecules in good to moderate yields through weak carbonyl chelation is reported. The reaction proceeds via a dual C-H bond activation where the first takes place selectively at benzylic position followed by second meta afford five-membered cyclic ring. An external ligand Ac-Gly-OH has been used succeed this protocol. plausible mechanism proposed for reaction.

Language: Английский

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Copper-Catalyzed Chemoselective (Amino)fluorosulfonylation of Hydrocarbons via Intramolecular Fluorine-Atom Transfer

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(6), P. 4318 - 4328

Published: March 6, 2024

Sulfonyl fluorides have found increasing applications as functional molecules in chemistry and biology. We herein report a copper-catalyzed atom-economical access to two categories of sulfonyl through radical relay strategy the presence an SO2 surrogate. The aliphatic C(sp3)–H bond N-fluoro-N-alkyl sulfonamides reacted via 1,5-hydrogen atom transfer (HAT) process, affording alkanesulfonyl with proximal amino group. On other hand, utilizing substrates containing proper C═C double resulted intramolecular olefin aminofluorosulfonylation, allowing synthesis fluorosulfonyl-functionalized pyrrolidines piperidines atom-transfer addition (ATRA). Both reaction systems proceeded under mild conditions, requiring no additional fluorine source. Experimental computational studies suggest that S–F coupling is likely achieved radical-rebound pathway. By taking advantage SuFEx multifunctionality products, method applicable late-stage modification bioactive compounds, drug ligation chemistry, organic synthesis.

Language: Английский

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Regio- and Diastereoselective Annulation of α,β-Unsaturated Aldimines with Alkenes via Allylic C(sp³)–H Activation by Rare-Earth Catalysts

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(14), P. 10187 - 10198

Published: March 28, 2024

The [3 + 2] or [4 annulation of α,β-unsaturated aldimines with alkenes via β′- γ-allylic C(sp3)–H activation is, in principle, an atom-efficient route for the synthesis five- six-membered-ring cycloalkylamines, which are important structural motifs numerous natural products, bioactive molecules, and pharmaceuticals. However, such a transformation has remained undeveloped to date probably due lack suitable catalysts. We report herein first time regio- diastereoselective annulations imines allylic by half-sandwich rare-earth catalysts having different metal ion sizes. reaction α-methyl-substituted C5Me4SiMe3-ligated scandium catalyst took place trans-diastereoselective fashion at α-methyl group (β′-position), exclusively affording alkylidene-functionalized cyclopentylamines excellent trans-diastereoselectivity. In contrast, β-methyl-substituted C5Me5-ligated cerium proceeded cis-diastereoselective activation, selectively yielding multisubstituted 2-cyclohexenylamines cis-diastereoselectivity. mechanistic details these transformations have been elucidated deuterium-labeling experiments, kinetic isotope effect studies, isolation key intermediates. This work offers efficient selective protocol new family cycloalkylamine derivatives, featuring 100% atom efficiency, high diastereoselectivity, broad substrate scope, unprecedented mechanism.

Language: Английский

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Divergent Synthesis of Multi‐Substituted Aminotetralins via [4+2] Annulation of Aldimines with Alkenes by Rare‐Earth‐Catalyzed Benzylic C(sp³)−H Activation

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(13)

Published: Jan. 16, 2024

The search for efficient and selective methods the divergent synthesis of multi-substituted aminotetralins is much interest importance. We report herein first time diastereoselective [4+2] annulation 2-methyl aromatic aldimines with alkenes via benzylic C(sp

Language: Английский

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Sulfonamide-directed site-selective functionalization of unactivated C(sp3)−H enabled by photocatalytic sequential electron/proton transfer

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: June 14, 2024

Abstract The generation of alkyl radical from C(sp 3 )−H substrates via hydrogen atom abstraction represents a desirable yet underexplored strategy in alkylation reaction since involving common concerns remain adequately unaddressed, such as the harsh conditions, limited substrate scope, and employment noble metal- or photo-catalysts stoichiometric oxidants. Here, we utilize synergistic photoredox transfer (HAT) catalysis to accomplish general practical functionalization unactived centers with broad high functional group compatibility, operational simplicity. A combination validation experiments density theory reveals that N-centered radicals, generated free N − H bond stepwise electron/proton event, are key intermediates enable an intramolecular 1,5-HAT intermolecular HAT process for nucleophilic carbon-centered radicals formation achieve heteroarylation, alkylation, amination, cyanation, azidation, trifluoromethylthiolation, halogenation deuteration. value this protocol is further demonstrated by gram-scale synthesis late-stage natural products drug derivatives.

Language: Английский

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Palladium-Catalyzed Annulations via Sequential C–H Activations of C(sp²)–H/C(sp³)–H or C(sp³)–H/C(sp³)–H Bonds

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(9), P. 6535 - 6546

Published: April 15, 2024

Palladium-catalyzed C–H annulation reactions represent a compelling strategy to construct complex ring systems with high step economy. While there are many approaches annulate structures by activation of single bond, transformations that proceed multiple bonds less explored. This is especially true for examples where one the reacting located at an sp3 center. However, exciting developments in palladium-catalyzed continue expand scope these and provide innovative strategies challenging carbon–carbon bonds. From discoveries, sequential activations have emerged as powerful tool access through C(sp2)–H/C(sp3)–H or C(sp3)–H/C(sp3)–H In this Perspective, we showcase recent use order highlight synthetic potential activation-enabled annulations inspire future disconnections diverse scaffold synthesis.

Language: Английский

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Synthesis of spirooxindolesviaformal acetylene insertion into a common palladacycle intermediate

Chemical Science, Journal Year: 2023, Volume and Issue: 14(21), P. 5650 - 5655

Published: Jan. 1, 2023

A palladium-catalyzed spirocyclization reaction is reported, which proposed to arise via insertion of an oxabicycle into a palladacycle, formed from carbocyclization and C-H functionalization sequence. Mechanistic studies suggest the diastereoselective post-catalytic retro-Diels-Alder step furnishes alkene, wherein oxibicycle has served as acetylene surrogate. Aryl iodides carbamoyl chlorides were compatible starting materials under same conditions, enabling convergent complementary synthesis spirooxindoles, well other azacycles. These spirooxindoles allowed further transformations that previously unaccessible.

Language: Английский

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Palladium(II)-Catalyzed Annulative Difunctionalization of Two Inert C(sp³)–H Bonds by a Bifunctional Reagent

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(11), P. 7627 - 7636

Published: May 22, 2023

Illustrated herein is a Pd(II)-catalyzed direct difunctionalization of two C(sp3)–H bonds aliphatic carboxylic acid derivatives by bifunctional reagents (BFRs) the 2-iodobenzoic series. The methyl 2-pyridyl sulfoximine (MPyS) bidentate directing group (DG), 2-chloro-5-trifluoromethylpyridine ligand, AgOAc as base, and NaBrO3 co-oxidant help concerted metalation deprotonation (CMD) inert bonds, well reductive elimination; density functional theory (DFT) studies shed light on these crucial steps. This process makes [C–C C–O] at gem-α,α′-di-Me groups in single operation, offering access to unusual benzo-fused peripheral-substituted caprolactones. transformation tolerates labile allows construction wide range caprolactones with structural diversity. Mechanistic reveal participation monomeric Pd species catalytic cycle. synthetic versatility complex molecular entities also presented.

Language: Английский

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