Bidentate Directing Groups: An Efficient Tool in C–H Bond Functionalization Chemistry for the Expedient Construction of C–C Bonds

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(3), P. 1788 - 1887

Published: Jan. 6, 2020

During the past decades, synthetic organic chemistry discovered that directing group assisted C–H activation is a key tool for expedient and siteselective construction of C–C bonds. Among various strategies, bidentate groups are now recognized as one most efficient devices selective functionalization certain positions due to fact its metal center permits fine, tunable, reversible coordination. The family permit types assistance be achieved, such N,N-dentate, N,O-dentate, N,S-dentate auxiliaries, which categorized based on coordination site. In this review, we broadly discuss bond reactions formation bonds with aid groups.

Language: Английский

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Transition-Metal-Catalyzed, Coordination-Assisted Functionalization of Nonactivated C(sp³)–H Bonds

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(24), P. 14957 - 15074

Published: Oct. 29, 2021

Transition-metal-catalyzed, coordination-assisted C(sp3)–H functionalization has revolutionized synthetic planning over the past few decades as use of these directing groups allowed for increased access to many strategic positions in organic molecules. Nonetheless, several challenges remain preeminent, such requirement high temperatures, difficulty removing or converting groups, and, although metals provide some reactivity, employing outside palladium. This review aims give a comprehensive overview coordination-assisted, transition-metal-catalyzed, direct nonactivated bonds by covering literature since 2004 order demonstrate current state-of-the-art methods well limitations. For clarity, this been divided into nine sections transition metal catalyst with subdivisions type bond formation. Synthetic applications and reaction mechanism are discussed where appropriate.

Language: Английский

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HFIP in Organic Synthesis

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(15), P. 12544 - 12747

Published: July 17, 2022

1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability stabilize ionic species, transfer protons, and engage range of other intermolecular interactions. The use this exponentially increased the past decade become choice some areas, such as C–H functionalization chemistry. In review, following brief history HFIP an overview physical properties, literature examples reactions using or additive are presented, emphasizing effect each reaction.

Language: Английский

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Overcoming the Limitations of γ- and δ-C–H Arylation of Amines through Ligand Development

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(51), P. 17884 - 17894

Published: Nov. 30, 2018

L,X-Type transient directing groups (TDGs) based on a reversible imine linkage have emerged as broadly useful tools for C–H activation of ketones and free amines. However, competitive binding interactions among multiple reaction components (TDG itself, substrate, substrate–TDG adduct) with the palladium catalyst often lead to formation unreactive complexes, rendering ligand development extremely challenging. Herein, we report finding versatile 2-pyridone ligands that addresses these problems significantly improves γ-methylene arylation alkyl amines, extending coupling partners wide range medicinally important heteroaryl iodides even previously bromides. The combination an appropriate group pyridone has also enabled δ-arylation Notably, our design reveals importance matching size Pd-chelation different palladacycles generated from γ- δ-C–H bonds: TDGs coordinate Pd(II) form six-membered chelate are selective toward γ-C–H bonds, whereas via five-membered tend activate bonds. These findings provide avenue developing protecting functionalization using strategy.

Language: Английский

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Palladium (II)‐Catalyzed C−H Activation with Bifunctional Ligands: From Curiosity to Industrialization

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: Feb. 29, 2024

Abstract In 2001, our curiosity to understand the stereochemistry of C−H metalation with Pd prompted first studies in Pd(II)‐catalyzed asymmetric activation (RSC Research appointment: 020 7451 2545, Grant: RG 36873, Dec. 2002). We identified four central challenges: 1. poor reactivity simple salts native substrates; 2. few strategies control site selectivity for remote bonds; 3. lack chiral catalysts achieve enantioselectivity via metalation, and 4. low practicality due limited coupling partner scope use specialized oxidants. These challenges necessitated new catalyst reaction development. For , we developed approaches enhance substrate–catalyst affinity together novel bifunctional ligands which participate accelerate cleavage step. site‐selectivity introduced concept systematically modulating distance geometry between a directing template, catalyst, substrate selectively access bonds. devised predictable stereomodels catalyst‐controlled enantioselective based on participation ligands. Finally, have varied catalytic manifolds Pd(II) accommodate diverse partners while employing practical oxidants such as peroxides. advances culminated numerous reactions, setting stage broad industrial applications.

Language: Английский

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β-C−H bond functionalization of ketones and esters by cationic Pd complexes

Nature, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Language: Английский

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Merging Photoinduced Electron Transfer with Hydrogen Atom Transfer: Formal β-C(sp³)–H Pyridination of Carbonyls

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 9, 2025

In this study, a novel approach that combines photoinduced electron transfer (ET) with hydrogen atom (HAT) has been introduced for the selective β-C(sp3)–H pyridination of carbonyl compounds. This method is notable its absence transition metals and ability to function under benign reaction conditions, resulting in range pyridinated derivatives consistently moderate good yields. The significance technique further underscored by potential late-stage functionalization pharmaceutically significant molecules. Mechanistic investigations confirmed proceeds via radical-mediated pathway.

Language: Английский

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α‐Aminoxy‐Acid‐Auxiliary‐Enabled Intermolecular Radical γ‐C(sp³)−H Functionalization of Ketones

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 57(6), P. 1692 - 1696

Published: Dec. 20, 2017

Abstract A method for site‐specific intermolecular γ‐C(sp 3 )−H functionalization of ketones has been developed using an α‐aminoxy acid auxiliary applying photoredox catalysis. Regioselective activation inert C−H bond is achieved by 1,5‐hydrogen atom abstraction oxidatively generated iminyl radical. Tertiary and secondary C‐radicals thus formed at the γ‐position imine functionality undergo radical conjugate addition to various Michael acceptors provide, after reduction hydrolysis, corresponding γ‐functionalized ketones.

Language: Английский

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Rhodium-Catalyzed Relay Carbenoid Functionalization of Aromatic C–H Bonds toward Fused Heteroarenes

Organic Letters, Journal Year: 2018, Volume and Issue: 20(5), P. 1396 - 1399

Published: Feb. 22, 2018

A rhodium-catalyzed annulation between ethyl benzimidates and α- aroyl sulfur ylides was developed, affording a series of pyrano[4,3,2-ij]isoquinoline derivatives in moderate to good yields with functional group compatibility. The procedure featured dual ortho-C–H functionalization cyclization one pot. optoelectronic properties those fused heteroarenes were tested by UV/vis fluorescence spectrometers.

Language: Английский

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Pd-Catalyzed, ortho C–H Methylation and Fluorination of Benzaldehydes Using Orthanilic Acids as Transient Directing Groups

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(8), P. 2789 - 2792

Published: Feb. 7, 2018

The direct, Pd-catalyzed ortho C-H methylation and fluorination of benzaldehydes have been accomplished using commercially available orthanilic acids as transient directing groups. In these reactions, the 1-fluoro-2,4,6-trimethylpyridinium salts can be either a bystanding F+ oxidant or an electrophilic fluorinating reagent. An X-ray crystal structure benzaldehyde palladation intermediate was obtained triphenylphosphine stabilizing ligand.

Language: Английский

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