Cobalt‐Catalyzed Radical Hydroamination of Alkenes with N‐Fluorobenzenesulfonimides

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(49), P. 25949 - 25957

Published: Sept. 25, 2021

An efficient and general radical hydroamination of alkenes using Co(salen) as catalyst, N-fluorobenzenesulfonimide (NFSI) its analogues both nitrogen source oxidant was successfully disclosed. A variety alkenes, including aliphatic styrenes, α, β-unsaturated esters, amides, acids, well enones, were all compatible to provide desired amination products. Mechanistic experiments suggest that the reaction underwent a metal-hydride-mediated hydrogen atom transfer (HAT) with alkene, followed by pivotal catalyst controlled SN 2-like pathway between in situ generated organocobalt(IV) species nitrogen-based nucleophiles. Moreover, virtue modified chiral cobalt(II)-salen an unprecedented asymmetric version also achieved good excellent level enantiocontrol. This novel C-N bond construction opens new door for challenging hydrofunctionalization.

Language: Английский

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Merging NiH Catalysis and Inner-Sphere Metal-Nitrenoid Transfer for Hydroamidation of Alkynes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(15), P. 5867 - 5877

Published: April 9, 2021

The formal hydroamination/hydroamidation utilizing metal hydride is an appealing synthetic tool for the construction of valuable nitrogen-containing compounds from unsaturated hydrocarbons. While significant advances have been made functionalizations alkenes in this realm, direct hydroamidation alkynes remains rather limited due to high feasibility key metal-alkenyl intermediate choose other reaction pathways. Herein, we report a NiH-catalyzed strategy with dioxazolones, which allows convenient access synthetically useful secondary enamides (E)-anti-Markovnikov or Markovnikov selectivity. viable both terminal and internal also tolerant range subtle functional groups. With H2O found as essential component catalyst turnovers, involvement inner-sphere nitrenoid transfer proposed that outcompetes undesired semireduction process, thus representing first example show competence Ni catalysis metal-nitrenoid formation dioxazolones.

Language: Английский

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Ligand-Controlled Cobalt-Catalyzed Regiodivergent Alkyne Hydroalkylation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(30), P. 13961 - 13972

Published: July 22, 2022

Regiodivergent alkyne hydroalkylation to generate different isomers of an alkene from the same starting material would be beneficial; however, it remains a challenge. Herein, we report ligand-controlled cobalt-catalyzed regiodivergent hydroalkylation. The sensible selection bisoxazoline (L1) and pyridine-oxazoline (L8) ligands led reliable predictable protocols that provided (E)-1,2-disubstituted 1,1-disubstituted alkenes with high E/Z stereoselectivity regioisomeric ratio identical terminal alkyl halide substrates produced trisubstituted in case internal alkynes. This method exhibits broad scope for alkynes wide range activated unactivated halides shows excellent functional group compatibility.

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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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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Cobalt‐Catalyzed Asymmetric Alkylation of (Hetero)Arenes with Styrenes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(26)

Published: April 1, 2022

An efficient and general intermolecular Cobalt(II)-catalyzed asymmetric alkylation of styrenes with (hetero)arenes including indoles, thiophene electron rich arenes has been developed, providing straightforward access to enantioenriched alkyl(hetero)arenes high enantioselectivity. Mechanistic studies suggest that the reaction underwent a CoH-mediated hydrogen atom transfer (HAT) alkenes, followed by pivotal catalyst-controlled SN 2-like pathway between in situ generated organocobalt(IV) species aromatic nucleophiles. This is first CoH-catalyzed hydrofunctionalization using carbon nucleophiles, new strategy for Friedel-Crafts type alkylation.

Language: Английский

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Ligand relay catalysis for cobalt-catalyzed sequential hydrosilylation and hydrohydrazidation of terminal alkynes

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Feb. 3, 2022

Sequential double hydrofunctionalizationalization of alkynes is a powerful method to construct useful vicinal compounds. Herein, we report cobalt-catalyzed sequential hydrosilylation/hydrohydrazidation afford 1,2-N,Si compounds via ligand relay catalysis. A phenomenon found that the tridentate anionic N-ligand (OPAQ) could capture cobalt ion from bidentate neutral P-ligand (Xantphos) complex. This protocol uses three abundant chemical feedstocks, alkynes, silanes, and diazo compounds, also features operationally simple, mild conditions, low catalyst loading (1 mol%), excellent functional group tolerance. The can be easily further derivatized various substituted silane derivatives Si-H functionalization, alcohols Fleming-Tamao oxidation, free amines amides N-N bond cleavage protection. asymmetric reaction carried out chiral products with up 86% ee. has been supported by control experiments absorption spectra.

Language: Английский

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Cobalt‐Catalyzed Enantioselective Hydroamination of Arylalkenes with Secondary Amines

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(2)

Published: Nov. 7, 2022

Abstract Catalytic asymmetric hydroamination of alkenes with Lewis basic amines is great interest but remains a challenge in synthetic chemistry. Here, we developed Co‐catalyzed arylalkenes directly using commercially accessible secondary amines. This process enables the efficient access to valuable α ‐chiral tertiary good excellent yields and enantioselectivities. Mechanistic studies suggest that reaction includes CoH‐mediated hydrogen atom transfer (MHAT) arylalkenes, followed by pivotal catalyst controlled S N 2‐like pathway between situ generated electrophilic cationic alkylcobalt(IV) species free radical‐polar crossover strategy not only provides straightforward alternative approach for synthesis enantioenriched ‐tertiary amines, also underpins substantial opportunities developing radical functionalization various nucleophiles oxidative MHAT catalysis.

Language: Английский

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Recent Advances in the Functionalization of Terminal and Internal Alkynes

Asian Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 11(5)

Published: March 9, 2022

Abstract Alkynes are one of the most fundamental and diverse functional groups utilized in organic synthesis. Over past few years, development efficient synthetic methodologies for functionalization alkynes has been an active area research. A plethora alkyne reactions have reported literature to construct functionalized alkene scaffolds, which important building blocks many natural products, pharmaceuticals, key intermediates various transformations. In this review, we describe recent advances with emphasis on substrate scope, limitations, regioselectivity control applications these reactions. This review covers from 2016 2021.

Language: Английский

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Magnesium Pincer Complexes and Their Applications in Catalytic Semihydrogenation of Alkynes and Hydrogenation of Alkenes: Evidence for Metal–Ligand Cooperation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(41), P. 19115 - 19126

Published: Oct. 4, 2022

The development of catalysts for environmentally benign organic transformations is a very active area research. Most the reported so far are based on transition-metal complexes. In recent years, examples catalysis by main-group metal compounds have been reported. Herein, we report series magnesium pincer complexes, which were characterized NMR and X-ray single-crystal diffraction. Reversible activation H2 via aromatization/dearomatization metal–ligand cooperation was studied. Utilizing obtained unprecedented homogeneous catalyzed semihydrogenation alkynes hydrogenation alkenes demonstrated under base-free conditions, affording Z-alkenes alkanes as products, respectively, with excellent yields selectivities. Control experiments DFT studies reveal involvement in reactions. This study not only provides new approach but also offers opportunities other

Language: Английский

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