Alkenyl Boronates: Synthesis and Applications

Chemistry - An Asian Journal, Journal Year: 2018, Volume and Issue: 14(3), P. 329 - 343

Published: Dec. 12, 2018

Abstract Organoboron compounds have become one of the most versatile building blocks in organic synthesis owing to their accessible and efficient conversion into many different functional groups. In particular, alkenyl boronates received a great deal attention as very reactive substrates Suzuki–Miyaura cross‐coupling reactions. Accordingly, efforts towards development methods prepare this type compound are ongoing. contribution, progress search for synthetic routes use variety transformations is accounted.

Language: Английский

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Transition Metal-Free 1,2-Carboboration of Unactivated Alkenes

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(20), P. 6221 - 6225

Published: May 9, 2018

A method for transition metal-free 1,2-carboboration of unactivated alkenes with bis(catecholato)diboron as the boron source in combination alkyl halides component is introduced. The three-component reaction proceeds via a radical pathway on broad range alkenes, and products serve valuable synthetic building blocks. Density functional theory calculations provide insights into mechanism.

Language: Английский

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Radical Addition to Strained σ-Bonds Enables the Stereocontrolled Synthesis of Cyclobutyl Boronic Esters

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(24), P. 9511 - 9515

Published: May 29, 2019

While radical additions to π-bonds are well established, σ-bonds far less explored. We have found that electron deficient radicals derived from alkyl iodides under visible light irradiation add the central strained bond of bicyclobutyl (BCB)-boronate complexes and lead 1,3-alkyl disubstituted cyclobutyl boronic esters in high yields, with full stereospecificity levels stereoselectivity. Novel cyclobutyl-substituted structures, including peptide steroid ester derivatives can be accessed. Additionally, although use electron-rich as precursors was ineffective, an alternative route involving alkylsulfonylation BCB-boronate followed by reductive desulfonylation provided access simple substituted cyclobutane products.

Language: Английский

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Visible Light Assisted Radical‐Polar/Polar‐Radical Crossover Reactions in Organic Synthesis

Advanced Synthesis & Catalysis, Journal Year: 2021, Volume and Issue: 363(13), P. 3146 - 3169

Published: April 10, 2021

Abstract Chemists are generally familiar with polar reactions and radical reactions, in comparison, underdeveloped. In the last few years, however, novel concept of amalgamation above two form radical‐polar crossover (RPCO) polar‐radical (PRCO) has emerged as a valuable powerful tool. This methodology tends to bridge gap between well overcomes limitations both traditional chemistry. By bringing together unorthodox chemistry radicals orthodox carbocations carbanions, green quotient such is significantly improved. The development shaping up this area years synthetically important transformations summarised review. magnified image

Language: Английский

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Photoinitiated Three-Component α-Perfluoroalkyl-β-heteroarylation of Unactivated Alkenes via Electron Catalysis

Organic Letters, Journal Year: 2018, Volume and Issue: 21(1), P. 325 - 329

Published: Dec. 21, 2018

A visible-light-initiated α-perfluoroalkyl-β-heteroarylation of various alkenes with perfluoroalkyl iodides and quinoxalin-2(1H)-ones is presented. This three-component radical cascade reaction allows an efficient synthesis a range containing quinoxalin-2(1H)-one derivatives in moderate to excellent yields under mild conditions. Reactions proceed via acidic aminyl radicals that are readily deprotonated give the corresponding anions able sustain chain as single electron transfer reducing reagents. Hence, overall classifies electron-catalyzed process.

Language: Английский

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Enantioselective Radical Addition/Cross‐Coupling of Organozinc Reagents, Alkyl Iodides, and Alkenyl Boron Reagents

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(40), P. 14245 - 14249

Published: Aug. 7, 2019

Abstract A hybrid transition‐metal/radical process is described that results in the addition of organozinc reagents and alkyl halides across alkenyl boron an enantioselective catalytic fashion. The reaction can be accomplished both intermolecularly intramolecularly, providing useful product yields high enantioselectivities manifolds.

Language: Английский

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Photo-triggered self-catalyzed fluoroalkylation/cyclization of unactivated alkenes: synthesis of quinazolinones containing the CF₂R group

Green Chemistry, Journal Year: 2020, Volume and Issue: 23(1), P. 575 - 581

Published: Dec. 10, 2020

A photo-triggered self-catalyzed fluoroalkylation/cyclization of quinazolinones containing unactivated alkenes with various fluoroalkyl bromides has been developed.

Language: Английский

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An Olefinic 1,2‐Boryl‐Migration Enabled by Radical Addition: Construction ofgem‐Bis(boryl)alkanes

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(28), P. 9448 - 9452

Published: May 6, 2019

A series of in situ formed alkenyl diboronate complexes from Grignard reagents (commercially available or prepared bromides and Mg) with B2 Pin2 (bis(pinacolato)diboron) react diverse alkyl halides by a Ru photocatalyst to give various gem-bis(boryl)alkanes. Alkyl radicals add efficiently the complexes, adduct radical anions undergo radical-polar crossover, specifically, 1,2-boryl-anion shift boron α-carbon sp2 center. This transformation shows good functional-group compatibility can serve as powerful synthetic tool for late-stage functionalization complex compounds. Measurements quantum yield reveal that radical-chain mechanism is operative which diboronates acts reductive quencher excited state photocatalyst.

Language: Английский

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α-Borylalkyl radicals: their distinctive reactivity in modern organic synthesis

Chemical Communications, Journal Year: 2019, Volume and Issue: 56(1), P. 13 - 25

Published: Nov. 27, 2019

Organoborons are extremely important for synthetic organic chemistry; they can serve as advanced intermediates a variety of transformations. Such well-known transformation involves the loss boron moiety, creating alkyl radicals. Although these originally developed protocols radical generation remain in active use today, recent years their α-boryl carbon-centred radicals have been joined by new array strategies that offer unique reactivity to forge wider diversity organoborons often operate under mild and benign conditions. Herein, we will highlight stability α-borylalkyl remarkably advances order further utilise them C-C C-heteroatom bond formation. Their this purpose has reported over last decade an attempt guide community. Various transition-metal metal-free methods presented, more photoredox approaches discussed, mainly period 2009-2019.

Language: Английский

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Radical‐Induced 1,2‐Migrations of Boron Ate Complexes

Advanced Synthesis & Catalysis, Journal Year: 2019, Volume and Issue: 362(11), P. 2077 - 2087

Published: Dec. 24, 2019

Abstract 1,2‐Boron ate rearrangements represent a fundamental class of transformations to establish new C−C bonds while retaining the valuable boron moiety in product. In established ionic processes, complex is activated by an external electrophile induce 1,2‐migration from adjacent sp 3 or 2 carbon atom. Recently, two complementary radical polar crossover approaches have been explored for both classes, 1,2‐migrations and centers. This review describes general concepts this emerging research field summarizes recent developments radical‐induced carbon. magnified image

Language: Английский

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