Direct Synthesis of Multi(boronate) Esters from Alkenes and Alkynes via Hydroboration and Boration Reactions

ACS Catalysis, Journal Year: 2020, Volume and Issue: 11(1), P. 1 - 18

Published: Dec. 10, 2020

Multi(boronate) esters have been attracting increasing attention as versatile building blocks for the succinct and precise synthesis of complex molecules. However, there are a limited number efficient synthetic procedures available. In this respect, direct multiboration alkenes alkynes is undoubtedly an ideal route their synthesis. During past 30 years, catalytic systems based on transition-metals, organophosphines, bases, even catalyst-free systems, with heat or light irradiation straightforward preparation from developed. different numbers (up to 4) positional relationships adjacent boron moieties were obtained, which summarized discussed herein.

Language: Английский

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Enantioselective Nickel‐Catalyzed Migratory Hydrocyanation of Nonconjugated Dienes

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(48), P. 21436 - 21441

Published: Aug. 12, 2020

Abstract Metal‐catalyzed chain‐walking reactions have recently emerged as a powerful strategy to functionalize remote positions in organic molecules. However, protocol for nonconjugated dienes remains scarcely reported, and developments are currently ongoing. In this Communication, nickel‐catalyzed asymmetric hydrocyanation of involving process is demonstrated. The reaction exhibits excellent regio‐ chemoselectivity, wide range substrates were tolerated, delivering the products high yields enantioselectivities. Deuterium‐labeling experiments support process, which involves an iterative β‐H elimination reinsertion processes. Gram‐scale synthesis, regioconvergent experiments, downstream transformations gave further insights into potential transformation.

Language: Английский

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Migratory functionalization of unactivated alkyl bromides for construction of all-carbon quaternary centers via transposed tert-C-radicals

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Sept. 25, 2020

Abstract Despite remarkable recent advances in transition-metal-catalyzed C(sp 3 )−C cross-coupling reactions, there remain challenging bond formations. One class of such reactions include the formation tertiary -C(sp bonds, presumably due to unfavorable steric interactions and competing isomerizations alkyl metal intermediates. Reported herein is a Ni-catalyzed migratory 3,3-difluoroallylation unactivated bromides at remote centers. This approach enables facile construction otherwise difficult prepare all-carbon quaternary Key success this transformation an unusual functionalization via chain walking most sterically hindered ) center substrate. Preliminary mechanistic radical trapping studies with primary suggest unique mode C-radical generation through chain-walking followed by Ni–C homolysis. strategy complementary existing coupling protocols tert -alkyl organometallic or halide reagents, it expedient centers from easily available starting materials.

Language: Английский

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γ-Selective C(sp3)–H amination via controlled migratory hydroamination

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Sept. 27, 2021

Abstract Remote functionalization of alkenes via chain walking has generally been limited to C(sp 3 )–H bonds α and β polar-functional units, while γ -C(sp through controlled alkene transposition is a longstanding challenge. Herein, we describe NiH-catalyzed migratory formal hydroamination alkenyl amides achieved chelation-assisted control, whereby various amino groups are installed at the -position aliphatic chains. By tuning olefin isomerization ligand directing group optimization, -selective amination can be stabilization 6-membered nickellacycle by an 8-aminoquinoline subsequent interception aminating reagent. A range amines bond unactivated with varying alkyl lengths, enabling late-stage access value-added -aminated products. Moreover, employing picolinamide-coupled substrates, this approach further extended δ amination. The chain-walking mechanism pathway selectivity investigated experimental computational methods.

Language: Английский

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Advances in transition metal-free deborylative transformations of gem-diborylalkanes

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(36), P. 4346 - 4353

Published: Jan. 1, 2021

This article highlights recent advances on the base-promoted deborylative carbon–carbon and carbon–boron bond-forming reactions using gem-diborylalkanes as sources of α-borylcabanions.

Language: Английский

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Chain-walking reactions of transition metals for remote C–H bond functionalization of olefinic substrates

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(85), P. 11110 - 11130

Published: Jan. 1, 2021

Transition metal-assisted remote C–H bond activation at the non-classical reaction sites of various olefinic substrates with aid a chain-walking process is depicted in this feature article.

Language: Английский

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Enantioselective Cobalt-Catalyzed Cascade Hydrosilylation and Hydroboration of Alkynes to Access Enantioenriched 1,1-Silylboryl Alkanes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(33), P. 13124 - 13134

Published: Aug. 12, 2021

Enantioenriched 1,1-silylboryl alkanes possess silyl and boryl groups that are both connected to the same stereogenic carbon center at well-defined orientations. As these chiral multifunctionalized compounds potentially offer two synthetic handles, they highly valued building blocks in asymmetric synthesis as well medicinal chemistry. Despite potential usefulness, efficient approaches for their preparation scarce. Seeking address this deficiency, an enantioselective cobalt-catalyzed hydrosilylation/hydroboration cascade of terminal alkynes has been realized. This protocol constitutes impressive case chemo-, regio-, stereoselectivity wherein different hydrofunctionalization events exquisitely controlled by a single set metal catalyst ligand, operation which would usually require separate catalytic systems. Downstream transformations enantioenriched 1,1-silyboryl led various valuable compounds. Mechanistic studies suggest present reaction undergoes regioselective stereocontrolled sequential hydrosilylation hydroboration processes.

Language: Английский

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α-Boryl Organometallic Reagents in Catalytic Asymmetric Synthesis

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(16), P. 10660 - 10680

Published: Aug. 12, 2021

Recent years have witnessed an increase in the popularity of α-boryl organometallic reagents as versatile nucleophiles asymmetric synthesis. These compounds been adopted chemo- and stereoselective coupling reactions with a number different electrophiles. The resulting enantioenriched boronic esters can be applied stereospecific carbon-carbon or carbon-heteroatom bond construction reactions, enabling two-step strategy for complex structures high efficiency functional group compatibility. Due to these reasons, tremendous effort has devoted preparation enantiomerically enriched development related racemic prochiral materials. In this review, we describe enantio- diastereoselective that involve starting materials products showcase their synthetic utility.

Language: Английский

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Palladium-Catalyzed Asymmetric Sequential Hydroamination of 1,3-Enynes: Enantioselective Syntheses of Chiral Imidazolidinones

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(25), P. 11364 - 11376

Published: June 10, 2022

Pd-catalyzed sequential hydroamination of readily available 1,3-enynes is reported. The redox-neutral process provides an efficient route to synthesize a broad scope imidazolidinones, thiadiazolidines, and imidazolidines. Asymmetric generates series synthetically valuable, enantioenriched imidazolidinones. Mechanistic studies revealed that the transformation occurred via intermolecular enyne pathway give allene intermediate. Subsequent intramolecular intermediate proceeded under Curtin-Hammett principle provide imidazolidinone products.

Language: Английский

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Ligand‐Controlled NiH‐Catalyzed Regiodivergent Chain‐Walking Hydroalkylation of Alkenes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(30)

Published: May 24, 2022

Abstract A NiH‐catalyzed migratory hydroalkylation of alkenyl amines with predictable and switchable regioselectivity is reported. By utilizing a ligand‐controlled, directing group‐assisted strategy, various alkyl units are site‐selectively installed at inert sp 3 C−H sites far away from the original C=C bonds. range structurally diverse α‐ β‐branched protected conveniently synthesized via stabilization 5‐ 6‐membered nickelacycles respectively. This method exhibits broad scope high functional group tolerance, can be applied to late‐stage modification medicinally relevant molecules.

Language: Английский

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