P-Chiral Phosphorus Ligands Based on a 2,3-Dihydrobenzo[d][1,3]oxaphosphole Motif for Asymmetric Catalysis

Accounts of Chemical Research, Journal Year: 2019, Volume and Issue: 52(4), P. 1101 - 1112

Published: March 8, 2019

Despite the rapid progress in field of asymmetric catalysis, search for new, efficient, and practical catalytic transformations to facilitate green synthesis chiral natural products drugs will continue be a major ongoing effort organic chemistry. Chiral phosphorus ligands have played significant role recent advances transition-metal-catalyzed transformations. However, there remain numerous challenging issues reactivity selectivity catalysis. The development new efficient with structural motifs remains highly desirable. P-Chiral been overlooked are underdeveloped, except early success DIPAMP, introduced first by Knowles 1970s. It was not until late 1990s that P-chiral regained attention advent bisP*, TangPhos, etc. Nonetheless, most were either difficult prepare or operationally inconvenient. practical, convenient an important subject research. This Account introduces design series bis- monophosphorus based on 2,3-dihydrobenzo[ d][1,3]oxaphosphole motif. Their unique physical properties include conformational unambiguousness, high tunability electronic steric properties, operational simplicity as air-stable solids, which make them exceptional bisphosphorus such MeO-BIBOP (L3), WingPhos (L4), iPr-BABIBOP (L7) demonstrated excellent enantioselectivities unprecedented turnover numbers (TONs) various hydrogenations other transformations, providing solutions leading amines, alcohols, carboxylic acids, α- β-amino acids. biaryl ligands, including BI-DIME (L9), AntPhos (L15), iPr-BI-DIME (L11), etc., proven class versatile powerful number Suzuki-Miyaura coupling, palladium-catalyzed dearomative cyclization, hydroboration/diboration, nickel-catalyzed reductive intramolecular arylation, alkene aryloxyarylation, α-arylation, Heck reaction, nucleophilic addition, synthetically structures biaryls, tertiary α-amino boronic esters, all-carbon quaternary stereocenters. TONs obtained these resulted syntheses several therapeutic agents concise manners. While our efforts ongoing, it should emphasized catalysts tackle current synthetic challenges. Such is destined promote catalysis well

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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P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

Chemical Reviews, Journal Year: 2024, Volume and Issue: 124(14), P. 8657 - 8739

Published: July 2, 2024

Chiral phosphorus ligands play a crucial role in asymmetric catalysis for the efficient synthesis of useful optically active compounds. They are largely categorized into two classes: backbone chirality and P-stereogenic ligands. Most reported belong to former class. Privileged ones such as BINAP DuPhos frequently employed wide range catalytic transformations. In contrast, latter class has remained small family many years mainly because their synthetic difficulty. The late 1990s saw emergence novel with superior enantioinduction ability Rh-catalyzed hydrogenation reactions. Since then, numerous have been synthesized used This Review summarizes thus far, including stereochemical electronic properties that afford high excellent enantioselectivities. Examples reactions use this described together applications construction key intermediates natural products therapeutic agents. literature covered dates back 1968 up until December 2023, centering on studies published later years.

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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Metal-catalyzed cross-coupling chemistry with polyhedral boranes

Chemical Communications, Journal Year: 2018, Volume and Issue: 55(4), P. 430 - 442

Published: Nov. 28, 2018

Over the past several decades, metal-catalyzed cross-coupling has emerged as a powerful strategy to functionalize polyhedral borane clusters.

Language: Английский

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Palladium-Catalyzed Selective Five-Fold Cascade Arylation of the 12-Vertex Monocarborane Anion by B–H Activation

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(42), P. 13798 - 13807

Published: Sept. 19, 2018

A series of cage penta-arylated carboranes have been synthesized by palladium-catalyzed intermolecular coupling the C-carboxylic acid monocarba- closo-dodecaborate anion [CB11H12]- with iodoarenes direct B-H bond functionalization. These transformations set a record in terms one-pot directing group-mediated activation inert bonds single molecule. The methodology is characterized high yields, good functional group tolerance, and complete regioselectivity. COOH can be easily removed during or after reaction. mechanistic pathways were probed using density theory calculations. Pd(II)-Pd(IV)-Pd(II) catalytic cycle proposed, which initial followed preferred adjacent boron vertex, continuation this selectivity results continuous walking process palladium center. opens new avenue toward building blocks 5-fold symmetry.

Language: Английский

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Recent Advances in Transition Metal-Catalyzed Selective B-H Functionalization ofo-Carboranes

Bulletin of the Chemical Society of Japan, Journal Year: 2020, Volume and Issue: 94(3), P. 879 - 899

Published: Dec. 18, 2020

Abstract Carboranes are a class of carbon-boron molecular clusters, possessing extraordinary characteristics including three-dimensional aromaticity conjugated by σ-bonds, icosahedral geometry and inherent robustness. They finding growing applications as valuable building blocks in boron neutron capture therapy agents, pharmacophores, nanomaterials, optoelectronic, organometallic/coordination chemistry more. Therefore, the effective controlled functionalization carboranes has attracted enormous research interests, particularly regio- enantio-selective cage BH derivatization among ten chemically similar vertices o-carboranes. Only recent few years, significant progress been made transition metal catalyzed vertex-specific functionalization. This review summarizes advances this realm.

Language: Английский

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Enantioselective Synthesis of Inherently Chiral Calix[4]arenes via Palladium-Catalyzed Asymmetric Intramolecular C–H Arylations

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(50), P. 22858 - 22864

Published: Dec. 8, 2022

We report herein an efficient approach for the enantioselective synthesis of inherently chiral calix[4]arenes via palladium-catalyzed asymmetric intramolecular C–H arylations. Using a bifunctional phosphine-carboxylate ligand, inherent chirality on macrocyclic scaffolds was induced successfully, from which wide range with fluorenone motifs were obtained good yields and excellent enantioselectivities (up to >99% ee). The synthetic utility this method demonstrated by diverse transformations products, thus substantially expanding chemical space calix[4]arenes. Further investigations photophysical chiroptical properties revealed that bearing two moieties displayed remarkable glum values 0.019), highlighting great potential in development organic optoelectronic materials.

Language: Английский

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