Paired Electrolysis-Enabled Arylation of Quinoxalin-2(1H)-ones

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(9), P. 6117 - 6125

Published: April 24, 2024

The first paired electrolysis-enabled arylation of quinoxalin-2(1H)-ones was achieved using cyanoarenes as the reagents. A variety 3-arylquinoxalin-2(1H)-ones with various important functional groups were obtained in moderate to good yields under metal- and chemical oxidant-free conditions. With a pair reductive oxidative processes occurring among substrates reaction intermediates, power consumption can be dramatically reduced.

Language: Английский

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Selective Coupling of 1,2‐Bis‐Boronic Esters at the more Substituted Site through Visible‐Light Activation of Electron Donor–Acceptor Complexes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(18)

Published: Feb. 25, 2022

1,2-Bis-boronic esters are useful synthetic intermediates particularly as the two boronic can be selectively functionalized. Usually, less hindered primary ester reacts, but herein, we report a coupling reaction that enables reversal of this selectivity. This is achieved through formation boronate complex with an electron-rich aryllithium which, in presence electron-deficient aryl nitrile, leads to electron donor-acceptor complex. Following visible-light photoinduced transfer, radical generated which isomerizes more stable secondary before radical-radical arene radical-anion, giving β-aryl products. The reactions proceed under catalyst-free conditions. method also allows stereodivergent cyclic cis-1,2-bis-boronic provide trans-substituted products, complementing selectivity observed Suzuki-Miyaura reaction.

Language: Английский

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The Impact of Boron Hybridisation on Photocatalytic Processes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(38)

Published: June 24, 2022

Recently the fruitful merger of organoboron chemistry and photocatalysis has come to forefront organic synthesis, resulting in development new technologies access complex (non)borylated frameworks. Central success this combination is control boron hybridisation. Contingent on photoactivation mode, as its neutral planar form or tetrahedral boronate can be used regulate reactivity. This Minireview highlights current state art photocatalytic processes utilising compounds, paying particular attention role hybridisation for target transformation.

Language: Английский

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Dual Nickel/Photoredox‐Catalyzed Site‐Selective Cross‐Coupling of 1,2‐Bis‐Boronic Esters Enabled by 1,2‐Boron Shifts

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(34)

Published: July 2, 2022

Abstract Site‐selective transition‐metal‐catalyzed mono‐deboronative cross‐couplings of 1,2‐bis‐boronic esters are valuable methods for the synthesis functionalized organoboron compounds. However, such limited to reaction sterically less hindered primary boronic ester. Herein, we report a nickel/photoredox‐catalyzed arylation that is selective coupling more secondary/tertiary position. This achieved by taking advantage 1,2‐boron shift β‐boryl radicals thermodynamically favored radicals, which subsequently intercepted nickel catalyst enable arylation. The mild conditions amenable broad range aryl halides give β‐aryl ester products in good yields and with high regioselectivity. method also allows stereodivergent cyclic cis ‐1,2‐bis‐boronic trans ‐substituted products.

Language: Английский

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Ir‐Catalyzed Enantioselective Synthesis of gem‐Diborylalkenes Enabled by 1,2‐Boron Shift

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 15, 2023

Abstract Asymmetric cross‐couplings based on 1,2‐carbon migration from B‐ate complexes have been developed efficiently to access valuable organoboronates. However, enantioselective reactions triggered by 1,2‐boron shift remained be unaddressed synthetic challenge. Here, Ir‐catalyzed asymmetric allylic alkylation enabled was developed. In this reaction, we disclosed that excellent enantioselectivities were achieved through an interesting dynamic kinetic resolution (DKR) process of carbonates at the elevated temperature. Notably, highly (bis‐boryl)alkenes array diversifications versatile molecules. Extensive experimental and computational studies conducted elucidate reaction mechanism DKR clarify origin enantioselectivities.

Language: Английский

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Catalyst-Free C(sp²)-H Borylation through Aryl Radical Generation from Thiophenium Salts via Electron Donor–Acceptor Complex Formation

Organic Letters, Journal Year: 2022, Volume and Issue: 24(40), P. 7434 - 7439

Published: Oct. 3, 2022

Aryl borates lie at the heart of carbon–carbon bond couplings, and they are widely applied to synthesis functional materials, pharmaceutical compounds, natural products. Currently, synthetic methods for aryl mostly limited metal-catalyzed routes, nonmetallic strategies remain comparatively underdeveloped. Herein, we report a mild, scalable, visible-light-induced cross-coupling between dibenzothiophenium triflate salts bis(catecholato)-diboron construction C–B bonds in absence base, transition metal–ligand complex, or photoredox catalyst. Mechanistic studies reveal that this transformation is achieved through an electron donor–acceptor (EDA) complex activation The mild reaction conditions allow preparation aromatic good yields with excellent group tolerance. This photochemical protocol was also successfully late-stage modification products drug intermediate, greatly demonstrating broadened utility.

Language: Английский

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Photocatalyzed regioselective hydrosilylation for the divergent synthesis of geminal and vicinal borosilanes

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: May 2, 2023

Geminal and vicinal borosilanes are useful building blocks in synthetic chemistry material science. Hydrosilylation/hydroborylation of unsaturated systems offer expedient access to these motifs. In contrast the well-established transition-metal-catalyzed methods, radical approaches rarely explored. Herein we report synthesis geminal from α-selective hydrosilylation alkenyl boronates via photoinduced hydrogen atom transfer (HAT) catalysis. Mechanistic studies implicate that α-selectivity originates a kinetically favored addition an energetically HAT process. We further demonstrate selective through allyl 1,2-boron migration. These strategies exhibit broad scopes across primary, secondary, tertiary silanes various boron compounds. The utility is evidenced by multi-borosilanes diverse fashion scaling up continuous-flow synthesis.

Language: Английский

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Radical Decyanations of Unactivated Carbon‐CN Bonds: Recent Achievements and Mechanistic Studies

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(13), P. 2058 - 2091

Published: May 17, 2023

Abstract Decyanation is an important process in the synthesis of aromatic molecules studies pharmaceutical research, medical and materials sciences. In late‐stage modifications privileged carbo/heterocyclic scaffolds, radical‐type decyanation techniques have been devised to date. As a result, chemistry cyano‐involved conversions, hotly debated subject over past few decades, has advanced significantly. The cyano group (CN), on other hand, rarely acknowledged as good reaction site due its thermodynamic robustness. most recent advancements catalytic radical protocols that CN behaved leaving made are surveyed this article. Following introduction number different modes, reactions used activate C−CN bonds primarily categorized, text herein divided into three groups: (1) photo‐catalyzed transformations, (2) electro‐catalyzed (3) transition‐metal‐catalyzed or metal‐free transformations. With emphasis systems synthetic applications bond activation, review will provide readers with overview reactions.

Language: Английский

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Enantioselective Suzuki cross-coupling of 1,2-diboryl cyclopropanes

Chemical Science, Journal Year: 2023, Volume and Issue: 14(6), P. 1575 - 1581

Published: Jan. 1, 2023

Herein, we describe the catalytic enantioselective cross-coupling of 1,2-bisboronic esters. Prior work on group specific cross coupling is limited to use geminal bis-boronates. This desymmetrization provides a novel approach prepare enantioenriched cyclopropyl boronates with three contiguous stereocenters, that could be further derivatized through selective functionalization carbon-boron bond. Our results suggest transmetallation, which enantiodetermining step, takes place retention stereochemistry at carbon.

Language: Английский

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Base‐Modulated 1,3‐Regio‐ and Stereoselective Carboboration of Cyclohexenes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(35)

Published: July 10, 2023

While chain-walking stimulates wide interest in both polymerization and organic synthesis, site- stereoselective control of on rings is still a challenging task the realm organometallic catalysis. Inspired by controllable cyclohexane olefin polymerization, we have developed set carboborations cyclohexenes based nickel Different from 1,4-trans-selectivity disclosed polymer science, high level 1,3-regio- cis-stereoselectivity obtained our reactions. Mechanistically, discovery that base affects reduction ability B2 pin2 different bases lead to catalytic cycles regioselective products (1,2- Vs 1,3-addition). This study provides concise modular method for synthesis 1,3-disubstituted cyclohexylboron compounds. The incorporation readily modifiable boronate group greatly enhances value this method, synthetic potential which was highlighted series high-valued commercial chemicals pharmaceutically interesting molecules.

Language: Английский

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