Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(18), P. 8347 - 8354

Published: April 28, 2022

Grignard addition is one of the most important methods used for syntheses alcohol compounds and has been known over a hundred years. However, research on asymmetric catalysis relies use organometallic nucleophiles. Here, we report first visible-light-induced cobalt-catalyzed reductive Grignard-type synthesizing chiral benzyl alcohols (>50 examples, up to 99% yield, ee). This methodology advantages mild reaction conditions, good functionality tolerance, excellent enantiocontrol, avoidance mass metal wastes, precious catalysts. Kinetic realization studies suggested that migratory insertion an aryl cobalt species into aldehyde was rate-determining step reaction.

Language: Английский

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Photoinduced Cobalt-Catalyzed Desymmetrization of Dialdehydes to Access Axial Chirality

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(12), P. 6944 - 6952

Published: March 15, 2023

Enantioselective metallaphotoredox catalysis, which combines photoredox catalysis and asymmetric transition-metal has become an effective approach to achieve stereoconvergence under mild conditions. Although many impressive synthetic approaches have been developed access central chirality, the construction of axial chirality by still remains underexplored. Herein, we report two visible light-induced cobalt-catalyzed reductive couplings biaryl dialdehydes synthesize axially chiral aldehydes (60 examples, up 98% yield, >19:1 dr, >99% ee). This protocol shows good functional group tolerance, broad substrate scope, excellent diastereo- enantioselectivity.

Language: Английский

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Cobalt-Catalyzed Sequential Site- and Stereoselective Hydrosilylation of 1,3- and 1,4-Enynes

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(12), P. 5233 - 5240

Published: March 17, 2022

Catalytic sequential hydrosilylation of 1,3-enynes and 1,4-enynes promoted by cobalt complexes derived from bisphosphines are presented. Site- stereoselective Si–H addition primary silanes to followed intramolecular diastereo- enantioselective afforded enantioenriched cyclic alkenylsilanes with simultaneous construction a carbon-stereogenic center silicon-stereogenic center. Reactions proceeded through isomerization the alkene moiety site- hydrosilylation. A wide range were in high efficiency selectivity. Functionalization containing stereogenic at silicon delivered variety chiral building blocks that otherwise difficult access.

Language: Английский

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Cobalt‐Catalyzed Asymmetric Aza‐Nozaki–Hiyama–Kishi (NHK) Reaction of α‐Imino Esters with Alkenyl Halides

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(7)

Published: Jan. 2, 2024

Chromium-catalyzed enantioselective Nozaki-Hiyama-Kishi (NHK) reaction represents one of the most powerful approaches for formation chiral carbon-heteroatom bond. However, construction sterically encumbered tetrasubstituted stereocenter through NHK still posts a significant challenge. Herein, we disclose cobalt-catalyzed aza-NHK ketimine with alkenyl halide to provide convenient synthetic approach manufacture enantioenriched α-vinylic amino acid. This protocol exhibits excellent functional group tolerance 99 % ee in cases. Additionally, this asymmetric reductive method is also applicable aldimine access trisubstituted stereogenic centers.

Language: Английский

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Cobalt‐Catalyzed Regio‐, Diastereo‐ and Enantioselective Intermolecular Hydrosilylation of 1,3‐Dienes with Prochiral Silanes

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

Published: May 24, 2022

Abstract One of the most straightforward approaches to access chiral silanes is catalytic enantioselective hydrosilylation. Although significant advances have been achieved in construction either a carbon‐stereogenic center or silicon‐stereogenic through hydrosilylation, simultaneous establishment carbon‐ and an acyclic molecule single intermolecular hydrosilylation remained undeveloped. Herein, unprecedented cobalt‐catalyzed regio‐, diastereo‐ 1,3‐dienes presented, enabling transformation. A wide range bearing were generated high efficiency stereoselectivity. Functionalization enantioenriched delivered variety valuable building blocks that are otherwise difficult access.

Language: Английский

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Decoding Key Transient Inter-Catalyst Interactions in a Reductive Metallaphotoredox-Catalyzed Allylation Reaction

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(24), P. 10912 - 10920

Published: June 8, 2022

Metallaphotoredox chemistry has recently witnessed a surge in interest within the field of synthetic organic through use abundant first-row transition metals combined with suitable photocatalysts. The intricate details arising from combination two (or more) catalytic components during reaction and especially inter-catalyst interactions remain poorly understood. As representative example process featuring such intricacies, we here present meticulous study mechanism cobalt-organophotoredox catalyzed allylation aldehydes. Importantly, commonly proposed elementary steps reductive metallaphotoredox are more complex than previously assumed. After initial quenching, transient charge-transfer forms that interacts both transition-metal catalyst base. Surprisingly, former interaction leads to deactivation due induced charge recombination, while latter promotes deprotonation electron donor, which is crucial step initiate productive catalysis but often neglected. Due low efficiency this process, overall photon-limited cobalt remains dual resting state, awaiting photoinduced reduction. These new insights general importance community, as become powerful tool used formation elusive compounds carbon–carbon bond formations. Understanding underlying aspects determine reactions provides conceptually stronger reactivity paradigm empower future approaches challenges rely on catalysis.

Language: Английский

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Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(50), P. 23001 - 23009

Published: Dec. 8, 2022

A new regio- and stereoselective reductive coupling of alkynes crotononitrile has been developed via visible light organophotoredox cobalt dual catalysis. variety enantioenriched homoallylic nitriles bearing a stereodefined trisubstituted alkene have easily synthesized with good to excellent (up >20:1 rr), stereo- (>20:1 E/Z), enantioselectivity 98% ee) control under mild conditions. The corresponding nitrile products were smoothly converted into various chiral building blocks. Remarkably, simple organic base together water utilized as hydrogen sources in this photoinduced reaction.

Language: Английский

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Metal-Catalyzed Enantioconvergent Transformations

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(20), P. 11817 - 11893

Published: Oct. 4, 2023

Enantioconvergent catalysis has expanded asymmetric synthesis to new methodologies able convert racemic compounds into a single enantiomer. This review covers recent advances in transition-metal-catalyzed transformations, such as radical-based cross-coupling of alkyl electrophiles with nucleophiles or alkylmetals and reductive two mainly under Ni/bis(oxazoline) catalysis. C–H functionalization can be performed an enantioconvergent manner. Hydroalkylation alkenes, allenes, acetylenes is alternative reactions. Hydrogen autotransfer been applied amination alcohols C–C bond forming reactions (Guerbet reaction). Other metal-catalyzed involve addition allylic systems carbonyl compounds, propargylation phenols, 3-bromooxindoles, allenylation allenolates propargyl bromides, hydroxylation 1,3-dicarbonyl compounds.

Language: Английский

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Cobalt-Catalyzed Diastereo- and Enantioselective Carbon–Carbon Bond Forming Reactions of Cyclobutenes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(6), P. 3588 - 3598

Published: Feb. 3, 2023

Catalytic enantioselective functionalization of cyclobutenes constitutes a general and modular strategy for construction enantioenriched complex cyclobutanes bearing multiple stereogenic centers, as chiral four-membered rings are common motifs in biologically active molecules versatile intermediates organic synthesis. However, synthesis through such remained significantly limited. Herein, we report series unprecedented cobalt-catalyzed carbon-carbon bond forming reactions that initiated carbometalation. The protocols feature diastereo- introduction allyl, alkynyl, functionalized alkyl groups. Mechanistic studies indicated an unusual 1,3-cobalt migration subsequent β-carbon elimination cascade process occurred the allyl addition. These new discoveries established elementary cobalt catalysis extension diversity nucleophiles transformations cyclobutenes.

Language: Английский

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Modular α-tertiary amino ester synthesis through cobalt-catalysed asymmetric aza-Barbier reaction

Nature Chemistry, Journal Year: 2023, Volume and Issue: 16(3), P. 398 - 407

Published: Dec. 11, 2023

Language: Английский

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