Methodologies and Strategies for Selective Borylation of C–Het and C–C Bonds

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(15), P. 7348 - 7398

Published: June 29, 2020

Organoborons have emerged as versatile building blocks in organic synthesis to achieve molecular diversity and carboxylic acid bioisosteres with broad applicability drug discovery. Traditionally, these compounds are prepared by the substitution of Grignard/lithium reagents electrophilic boron species Brown hydroboration. Recent developments provided new routes for efficient preparation organoborons applying reactions using chemical feedstocks leaving groups. As compared previous methods that used halides (I, Br, Cl), direct borylation less reactive C–Het C–C bonds has become highly important get efficiency functional-group compatibility. This Review aims provide a comprehensive overview this topic, including (1) C–F bond borylation, (2) C–O (3) C–S (4) C–N (5) borylation. Considerable attention is given strategies mechanisms involved. We expect will inspire chemists discover more transformations expand field.

Language: Английский

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Remote steric control for undirected meta -selective C–H activation of arenes

Science, Journal Year: 2022, Volume and Issue: 375(6581), P. 658 - 663

Published: Feb. 10, 2022

Regioselective functionalization of arenes remains a challenging problem in organic synthesis. Steric interactions are often used to block sites adjacent given substituent, but they do not distinguish the remaining remote sites. We report strategy based on steric control, whereby roof-like ligand protects distant para site addition ortho sites, and thereby enables selective activation meta carbon-hydrogen (C–H) bonds absence or substituents. demonstrate this concept for iridium-catalyzed -selective borylation various monosubstituted arenes, including complex drug molecules. This has potential expand toolbox C–H bond previously nondifferentiable reaction

Language: Английский

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tert‐Butyl Nitrite (TBN), a Multitasking Reagent in Organic Synthesis

Chemistry - An Asian Journal, Journal Year: 2019, Volume and Issue: 14(24), P. 4454 - 4492

Published: Sept. 20, 2019

The upsurge interest in the development of efficient methodologies for construction nitrogen-containing frameworks via use expedient reagents have been creating a renaissance contemporary organic chemistry. In this perspective, tertbutyl nitrite (TBN) is an emerging building block. Due to its unique structural features, it shows differential reactivity under different reaction conditions. These diverse reactivities resulted array complex N-containing molecules. primary objective present review bring latest findings TBN terms applications reactions (oxidation, diazotization, nitrosation, nitration, oximation, N-synthon, and miscellaneous reactions) into limelight. For simplicity brevity, each section are explained with mechanism formation selected examples given.

Language: Английский

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Meta Selective C–H Borylation of Sterically Biased and Unbiased Substrates Directed by Electrostatic Interaction

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(20), P. 7604 - 7611

Published: May 14, 2021

An electrostatically directed meta borylation of sterically biased and unbiased substrates is described. The follows an electrostatic interaction between the partially positive negative charges ligand substrate. With this strategy, it has been demonstrated that a wide number challenging substrates, especially 4-substituted can selectively be borylated at position. Moreover, unsubstituted also displayed excellent selectivity. reaction employs bench-stable proceeds milder temperature, precluding need to synthesize bulky sophisticated ligand/template.

Language: Английский

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Discovery of Oxygen α-Nucleophilic Addition to α,β-Unsaturated Amides Catalyzed by Redox-Neutral Organic Photoreductant

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(50), P. 20942 - 20947

Published: Dec. 2, 2020

The conjugate additions of oxygen-centered nucleophiles to acceptors are among the most powerful C–O bond formation reactions. addition normally takes place at β-position carbon electron-withdrawing group, resulting in a stabilized carbanion intermediate that can be quenched by proton or electrophiles form β-addition (i.e., hetero-Michael addition) products. On contrary, α-hydroxyl alkoxyl amides through needs an α,β-inverse addition. Nevertheless, regio-inversed nucleophilic α-addition α,β-unsaturated carbonyl compounds still remains less explored because electronic mismatch. In this research, we discovered first α-specific with oxygen and fluoride nucleophiles. This region-inversed is enabled catalysis novel redox-neutral nondonor–acceptor organic photoreductant (CBZ6). As low as 0.5 mol % visible light was employed. mechanistic insights were also explored. oxidative potential excited state CBZ6 obtained −1.92 V (vs SCE), presenting stronger reductive than representative metal-cored photoredox catalysts. feature umpolung take α-nucleophilic other normal β-addition.

Language: Английский

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Transition‐Metal‐Free Radical Borylation Reactions

European Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 26(12)

Published: Feb. 13, 2023

Abstract Organoboron compounds are versatile synthons in synthetic chemistry, materials science, and medicinal chemistry. The preparation of them often requires either reactive organometallic reagents or transition metals. In recent years, transition‐metal‐free borylation methodologies using radical chemistry for C−B bond formation have attracted much attention developed rapidly, which circumvents the use preformed reagents. Various successful approaches from different precursors (such as carboxylic acids, amines alcohols, abundant nature) through thermochemical, photochemical electrochemical pathways been developed. Therefore, this review, we hope to provide an overview advances discovery, development, mechanistic study processes.

Language: Английский

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Tunable Functionalization of Saturated C–C and C–H Bonds of N,N′-Diarylpiperazines Enabled by tert-Butyl Nitrite (TBN) and NaNO₂ Systems

Organic Letters, Journal Year: 2019, Volume and Issue: 21(13), P. 5030 - 5034

Published: June 25, 2019

A tunable functionalization of saturated C–C and C–H bonds N,N′-diarylpiperazine derivatives was realized by tert-butyl nitrite (TBN) NaNO2 systems, respectively. When TBN employed as the oxidant, bond cleavage occurred smoothly, providing a series formamides in good yields. In presence NaNO2, oxidation achieved, resulting efficient synthesis nitroalkenes. The mechanistic study shows that mixed mechanism is involved these reactions, which generated enamine might be key intermediate.

Language: Английский

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Photocatalytic Redox-Neutral C(sp³)–C(sp³) Cleaving Transalkylation of Heteroarenes

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

Published: May 2, 2025

In this work, a photocatalytic redox-neutral carbon-carbon bond metathesis and transalkylation of heteroarenes was established. When CBZ6 used as the photocatalyst, alkyl migration from 2-alkyl pyrrolidines or piperidines to heteroaryl nitriles occurred, affording heteroaryl-substituted tertiary ethers in up 98% yields. The cyanyl groups released nitrites are trapped by donors form 2-cyano piperidines. These can be recycled for regeneration donors. A wide range substrates has been proven suitable. Preliminary mechanistic investigations revealed nature reaction.

Language: Английский

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Decarboxylative Borylation of mCPBA-Activated Aliphatic Acids

Organic Letters, Journal Year: 2019, Volume and Issue: 22(1), P. 234 - 238

Published: Dec. 18, 2019

A decarboxylative borylation of aliphatic acids for the synthesis a variety alkylboronates has been developed by mixing m-chloroperoxybenzoic acid (mCPBA)-activated fatty with bis(catecholato)diboron in N,N-dimethylformamide (DMF) at room temperature. radical chain process is involved reaction which initiates from B–B bond homolysis followed transfer boron atom to carbon subsequent decarboxylation and borylation.

Language: Английский

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Radical Cyclization of 1,n‐Enynes and 1,n‐Dienes for the Synthesis of 2‐Pyrrolidone

Chemistry - An Asian Journal, Journal Year: 2021, Volume and Issue: 16(20), P. 3068 - 3081

Published: Aug. 23, 2021

Abstract 2‐Pyrrolidones have aroused enormous interest as a useful structural moiety in drug discovery; however, not only does their syntheses suffer from low selectivity and yield, but also it requires high catalyst loadings. The radical cyclization of 1, n ‐enynes ‐dienes has demonstrated to be an attractive method for the synthesis 2‐pyrrolidones due its mild reaction conditions, fewer steps, higher atom economy, excellent functional group compatibility, regioselectivity. Furthermore, receptors with unsaturated bonds (i. e. ‐dienes) play crucial role realizing because ability selectively introduce one or more sources. In this review, we discuss representative examples methods involving published last five years each prominent design mechanism, providing favorable tools valuable 2‐pyrrolidone variety applications.

Language: Английский

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