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

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(18), С. 8347 - 8354

Опубликована: Апрель 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.

Язык: Английский

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Photoinduced Cobalt-Catalyzed Desymmetrization of Dialdehydes to Access Axial Chirality

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(12), С. 6944 - 6952

Опубликована: Март 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.

Язык: 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, Год журнала: 2022, Номер 144(12), С. 5233 - 5240

Опубликована: Март 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.

Язык: Английский

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

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(30)

Опубликована: Май 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.

Язык: Английский

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

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(24), С. 10912 - 10920

Опубликована: Июнь 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.

Язык: Английский

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Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(50), С. 23001 - 23009

Опубликована: Дек. 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.

Язык: Английский

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Metal-Catalyzed Enantioconvergent Transformations

Chemical Reviews, Год журнала: 2023, Номер 123(20), С. 11817 - 11893

Опубликована: Окт. 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.

Язык: Английский

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

Nature Chemistry, Год журнала: 2023, Номер 16(3), С. 398 - 407

Опубликована: Дек. 11, 2023

Язык: Английский

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

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(6), С. 3588 - 3598

Опубликована: Фев. 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.

Язык: Английский

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Photocatalytic Metal Hydride Hydrogen Atom Transfer Mediated Allene Functionalization by Cobalt and Titanium Dual Catalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(24)

Опубликована: Апрель 12, 2023

Catalytic metal hydride hydrogen atom transfer (MHAT) reactions have proven to be a powerful method for alkene functionalization. This work reports the discovery of Co-porphines as highly efficient MHAT catalysts with loading only 0.01 mol % unprecedented chemoselective allene functionalization under photoirradiation. Moreover, newly developed bimetallic strategy by combination photo Co-MHAT and Ti catalysis enabled successful carbonyl allylation wide range amino, oxy, thio, aryl, alkyl-allenes providing expedient access valuable β-functionalized homoallylic alcohols in over 100 examples exceptional regio- diastereoselectivity. Mechanism studies DFT calculations supported that selectively transferring atoms from cobalt allenes generating allyl radicals is key step catalytic cycle.

Язык: Английский

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