Transient Directing Groups for Transformative C–H Activation by Synergistic Metal Catalysis

Chem, Journal Year: 2017, Volume and Issue: 4(2), P. 199 - 222

Published: Dec. 21, 2017

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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Controlled functionalization ofo-carboraneviatransition metal catalyzed B–H activation

Chemical Society Reviews, Journal Year: 2019, Volume and Issue: 48(13), P. 3660 - 3673

Published: Jan. 1, 2019

This review summarizes recent advances in transition metal catalyzed vertex-specific BH functionalization ofo-carborane for controlled synthesis of its derivatives.

Language: Английский

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Aggregation‐Induced Electrochemiluminescence of Carboranyl Carbazoles in Aqueous Media

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(10), P. 3162 - 3166

Published: Jan. 30, 2019

Abstract The aggregation‐induced electrochemiluminescence (AIECL) of carboranyl carbazoles in aqueous media was investigated for the first time. Quantum yields, morphologies, and particle sizes were observed to determine (ECL) performance these aggregated organic dots (ODs). All compounds exhibit much higher ECL stability intensity than carborane‐free compound, demonstrating essential role motif. Moreover, results cyclic voltammetry (CV) suggest that oxidation/reduction reactions take place at excited states ODs proposed be generated by mechanism surface state transitions. More importantly, show a reductive–oxidative contrast other materials oxidative–reductive mechanisms. Our experiments data have established relation between AIE structures properties has strong potential biological diagnostic applications.

Language: Английский

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A Strategy for Selective Catalytic B–H Functionalization of o-Carboranes

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(21), P. 4065 - 4079

Published: Oct. 24, 2021

ConspectusCarboranes are a class of polyhedral carbon-boron molecular clusters featuring three-dimensional aromaticity, which often considered as 3D analogues benzene. Their unique structural and electronic properties make them invaluable building blocks for applications ranging from functional materials to versatile ligands pharmaceuticals. Thus, selective functionalization carboranes has received tremendous research interest. In earlier days, the vast majority works in this area were focused on cage carbon via facile deprotonation CH, followed by reaction with electrophiles. On contrary, B-H activation is very challenging since 10 bonds o-carborane similar, how achieve desired transformation at specific boron vertex long-standing issue.As more electronegative than boron, property results different charges cage, follow order B(3,6)-H ≪ B(4,5,7,11)-H < B(8,10)-H B(9,12)-H. We thought that difference may trigger favorite interaction proper transition metal complex bond carborane, could be utilized solve selectivity issue. Accordingly, our strategy described follows: (1) electron-rich catalysts good most electron-deficient (connected both C-H vertices); (2) relatively B(8,9,10,12)-H (with no bonding either (3) directing-group-assisted catalysis appropriate only one vertex), whose lie middle range bonds. This been successfully applied laboratory other groups development series synthetic routes catalytic carborane resulting synthesis large number cage-boron-functionalized derivatives regioselective fashion. Subsequently, significant progress emerging made.In 2013 we reported tetrafluorination o-carboranes using an Pd(II) salt, [Pd(MeCN)4][BF4], catalyst. 2014 disclosed first example carboxy-directed alkenylation B(4) promoted Ir(III) 2017 presented Ir(I)-catalyzed diborylation also uncovered Pd-catalyzed asymmetric chiral-at-cage 2018. These proof-of-principle studies have greatly stimulated activities enabled catalysts. so far developed toolbox methods B-olefination, -arylation, -alkenylation, -alkynylation, -oxygenation, -sulfenylation, -borylation, -halogenation, -amination. recently expanded base catalysis. As field progresses, expect will invented, detailed Account promote these efforts.

Language: Английский

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Organocatalytic Asymmetric Synthesis of o-Carboranyl Amines

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 14, 2025

Carboranyl amines are distinct from typical organic amines. Due to the electronic influence of carborane cage, they have low nucleophilicity and reluctant alkylate. Moreover, asymmetric synthesis chiral carboranes is still in its infancy. Herein we achieved first catalytic N-alkylation o-carboranyl amine, providing general access diverse secondary with high efficiency enantioselectivity under mild conditions. For time, organocatalysis was introduced chemistry. Key success use situ generated (naphtho-)quinone methides as alkylating reagents suitable acid catalysts. This protocol also applicable S-alkylation 1-SH-o-C2B10H11. Control experiments kinetic studies provided important insights into reaction mechanism, which likely involves rate-determining generation quinone methide followed by fast enantio-determining nucleophilic addition.

Language: Английский

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Transient imines as ‘next generation’ directing groups for the catalytic functionalisation of C–H bonds in a single operation

Organic & Biomolecular Chemistry, Journal Year: 2018, Volume and Issue: 16(25), P. 4582 - 4595

Published: Jan. 1, 2018

C-H functionalisation promises a paradigm shift in synthetic planning. However, the additional steps often required to install and remove directing groups currently detract from efficiency. The strategy of reversible installation group via an imine linkage has recently emerged, with formed hydrolysed situ. Such transient can promote transition metal catalysed unactivated bonds aldehydes, ketones amines. This approach removes usually for covalent use catalytic quantities forming component. review updates rapidly developing field on sp2 sp3 carbon centres, form new C-C C-X bonds. We focus structures as mono or bidentate coordinating various catalysts.

Language: Английский

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Transition‐Metal‐Catalyzed Selective Cage B−H Functionalization of o‐Carboranes

Chemistry - A European Journal, Journal Year: 2017, Volume and Issue: 24(12), P. 2795 - 2805

Published: Nov. 17, 2017

Abstract Carboranes are a class of carbon–boron molecular clusters with unusual thermal and chemical stabilities. They have been proved as very useful building blocks in supramolecular design, optoelectronics, nanomaterials, boron neutron capture therapy agents organometallic/coordination chemistry. Thus, the functionalization o ‐carboranes has received growing interests. Over past decades, most works this area focused on cage carbon weakly acidic C−H proton can be readily deprotonated by strong bases. In sharp contrast, selective B−H activation/functionalization among chemically similar ten vertices is challenging. Considering differences electron density bonds ‐carborane nature transition metal complexes, we tackled selectivity issue means organometallic Our strategy follows: using electron‐rich catalysts for electron‐deficient B(3,6)−H (bonded to both CH vertices); transition‐metal relatively B(8,9,10,12)−H (with no bonding combination directing groups electrophilic B(4,5,7,11)−H only one vertex). Successful applications such result preparation large variety B‐functionalized carboranes regioselective catalytic manner, which inaccessible other means. It believed that field progresses, expected synthesized, results detailed concept article will further these efforts.

Language: Английский

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Palladium-catalyzed enantioselective C(sp²)–H arylation of ferrocenyl ketones enabled by a chiral transient directing group

Chemical Communications, Journal Year: 2017, Volume and Issue: 54(6), P. 689 - 692

Published: Dec. 21, 2017

Palladium-catalyzed enantioselective C(sp2)-H activation of ferrocenyl ketones is achieved through utilizing catalytic, inexpensive l-tert-leucine as a chiral transient directing group. The transformation allows rapid access to ferrocene scaffolds simultaneously possessing planar- and stereogenic central chirality, widely applied in the ferrocene-based ligand families.

Language: Английский

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Transient‐Ligand‐Enabled ortho ‐Arylation of Five‐Membered Heterocycles: Facile Access to Mechanochromic Materials

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(13), P. 3401 - 3405

Published: Jan. 30, 2018

Abstract Reported herein is the first example of a direct arylation heteroarenes by transient‐ligand‐directed strategy without need to construct and deconstruct directing group. A wide range undergoes coupling with diverse aryl iodides assemble large library highly selective functionalized 3‐arylthiophene‐2‐carbaldehydes. This route provides an opportunity rapidly access new mechanofluorochromic materials. Moreover, novel for mechanochromic luminogens chromism trends red‐ blue‐shifts has been disclosed time facile functional‐group modifications common structural core.

Language: Английский

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