Advances in theE → ZIsomerization of Alkenes Using Small Molecule Photocatalysts

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2650 - 2694

Published: Aug. 27, 2021

Geometrical E → Z alkene isomerization is intimately entwined in the historical fabric of organic photochemistry and enjoying a renaissance (Roth et al. Angew. Chem., Int. Ed. Engl. 1989 28, 1193–1207). This consequence fundamental stereochemical importance Z-alkenes, juxtaposed with frustrations thermal reactivity that are rooted microscopic reversibility. Accessing excited state paradigms allow this latter obstacle to be circumnavigated by exploiting subtle differences photophysical behavior substrate product chromophores: provides molecular basis for directionality. While direct irradiation operationally simple, photosensitization via selective energy transfer enables augmentation repertoire include substrates not directly photons. Through sustained innovation, an impressive portfolio tailored small molecule catalysts range triplet energies now widely available facilitate contra-thermodynamic thermo-neutral reactions generate Z-alkene fragments. review intended serve as practical guide covering geometric alkenes enabled catalysis from 2000 2020, logical sequel excellent treatment Dugave Demange (Chem. Rev. 2003 103, 2475–2532). The mechanistic foundations underpinning selectivity discussed together induction models rationales explain counterintuitive directionality these processes which very distinguish product. Implications subsequent stereospecific transformations, application total synthesis, regioselective polyene isomerization, spatiotemporal control pre-existing configuration broader sense discussed.

Language: Английский

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First-Row d-Block Element-Catalyzed Carbon–Boron Bond Formation and Related Processes

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(21), P. 13238 - 13341

Published: Oct. 7, 2021

Organoboron reagents represent a unique class of compounds because their utility in modern synthetic organic chemistry, often affording unprecedented reactivity. The transformation the carbon–boron bond into carbon–X (X = C, N, and O) stereocontrolled fashion has become invaluable medicinal agrochemistry, natural products chemistry as well materials science. Over past decade, first-row d-block transition metals have increasingly widely used catalysts for formation bond, traditionally catalyzed by expensive precious metals. This recent focus on alternative enabled growth fundamental methods organoboron chemistry. review surveys current state-of-the-art use element-based bonds.

Language: Английский

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Organic Photoredox-Catalyzed Silyl Radical Generation from Silylboronate

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(13), P. 7804 - 7810

Published: June 16, 2022

A visible-light-driven silyl radical generation method from silylboronates has been developed. The activation of with a catalytic amount mild base promoted the single-electron oxidation process to form radicals. Facile single electron transfer for borate readily occurred without hydrogen atom hydrosilane in presence various photoredox catalysts. Combining this protocol radical-mediated N-heterocyclic carbene catalysis enabled acylsilylation alkenes via relay generation. Furthermore, recent advanced methods synthesis significantly improved utility process.

Language: Английский

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A Combined Computational and Experimental Study of Rh-Catalyzed C–H Silylation with Silacyclobutanes: Insights Leading to a More Efficient Catalyst System

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(9), P. 3571 - 3582

Published: Feb. 23, 2021

The study of new C–H silylation reagents and reactions remains an important topic. We reported that under Rh catalysis, silacyclobutanes (SCBs) for the first time were able to react with C(sp2)–H C(sp3)–H bonds, however underlying reasons such a reactivity not understood. Through this combined computational experimental on SCBs, we only depict reaction pathway fully accounts all findings but also streamline more efficient catalyst significantly improves rates yields. Our key include: (1) active catalytic species is [Rh]–H as opposed previously proposed [Rh]–Cl; (2) generated via reductive elimination/β-hydride (β-H) elimination sequence, endocyclic β-H elimination; (3) regio- enantio-determining steps are identified; (4) same importance, discretely synthesized shown be catalyst. This work suggests [Rh]–H/diphosphine system should find further applications in silylations involving SCBs.

Language: Английский

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Inorganometallics (Transition Metal–Metalloid Complexes) and Catalysis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(3), P. 3996 - 4090

Published: Dec. 30, 2021

While the formation and breaking of transition metal (TM)-carbon bonds plays a pivotal role in catalysis organic compounds, reactivity inorganometallic species, that is, those involving (TM)-metalloid (E) bond, is key importance most conversions metalloid derivatives catalyzed by TM complexes. This Review presents background its development over last 15 years. The results mechanistic studies presented are related to occurrence TM-E TM-H compounds as reactive intermediates catalytic transformations selected metalloids (E = B, Si, Ge, Sn, As, Sb, or Te). illustrates significance inorganometallics following processes: addition metalloid-hydrogen metalloid-metalloid unsaturated compounds; activation functionalization C-H C-X with hydrometalloids bismetalloids; vinylmetalloids, halides, sulfonates; dehydrocoupling hydrometalloids. first on sums up developments methods for synthesis organometalloid their applications advanced part tandem reactions.

Language: Английский

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Salt‐Stabilized Silylzinc Pivalates for Nickel‐Catalyzed Carbosilylation of Alkenes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(17)

Published: Feb. 18, 2022

Abstract We herein report the preparation of solid and salt‐stabilized silylzinc pivalates from corresponding silyllithium reagents via transmetalation with Zn(OPiv) 2 . These resulting organosilylzinc show enhanced air moisture stability unique reactivity in silylative difunctionalization alkenes. Thus, a practical chelation‐assisted nickel‐catalyzed regioselective alkyl benzylsilylation alkenes has been developed, which provides an easy method to access silanes broad substrate scope wide functional group compatibility. Kinetic experiments highlight that OPiv‐coordination is crucial improve pivalates. Furthermore, late‐stage functionalizations druglike molecules versatile modifications products illustrate synthetical utility this protocol.

Language: Английский

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Unleashing the potentiality of metals: synergistic catalysis with light and electricity

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(14), P. 4024 - 4040

Published: Jan. 1, 2024

This review provides a comprehensive overview of metal catalysis in photo-electrochemical systems, discussing reaction mechanisms and offering prospects for this triadic catalytic mode.

Language: Английский

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Copper-Catalyzed General and Selective α-C(sp³)–H Silylation of Amides via 1,5-Hydrogen Atom Transfer

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(3), P. 1725 - 1732

Published: Jan. 18, 2024

The development of a general and selective method for α-C(sp3)–H silylation feedstock amines has been long-standing challenge. In this paper, we disclose mild, general, practical, highly regio- diastereoselective various readily available acyclic, cyclic, aromatic with silylboranes through copper-catalyzed intramolecular 1,5-hydrogen atom transfer (HAT) strategy. mild activation 2-iodobenzamide to generate an aryl radical enabled by ligand-coordinated silyl copper complex without additional heating or photoinduced conditions, as well the 1,5-HAT process produce crucial α-aminoalkyl species, is key success chemistry. This protocol demonstrated its potential utility in late-stage modification structurally drugs bioactive molecules. Therefore, it expected that will find applications synthetic chemistry drug discovery.

Language: Английский

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Silyl Radical Generation from Silylboronic Pinacol Esters through Substitution with Aminyl Radicals

Organic Letters, Journal Year: 2024, Volume and Issue: 26(5), P. 1011 - 1016

Published: Jan. 30, 2024

A novel strategy was developed to generate silyl radicals from silylboronic pinacol esters (SPEs) through nucleohomolytic substitution of boron with aminyl radicals. We successfully applied this obtain diverse organosilicon compounds using SPEs and N-nitrosamines under photoirradiation without any catalyst. The ability access offers a new perspective for chemists rapidly construct Si–X bonds.

Language: Английский

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Catalyst-free carbosilylation of alkenes using silyl boronates and organic fluorides via selective C-F bond activation

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

Published: June 18, 2021

Abstract A regioselective carbosilylation of alkenes has emerged as a powerful strategy to access molecules with functionalized silylated alkanes, by incorporating silyl and carbon groups across an alkene double bond. However, the best our knowledge, organic fluorides have never been used in this protocol. Here we disclose catalyst-free using boronates mediated t BuOK. The main feature transformation is selective activation C-F bond fluoride boronate without undergoing potential side-reactions involving C-O, C-Cl, heteroaryl-CH, even CF 3 groups. Various alkanes tertiary or quaternary centers that aromatic, hetero-aromatic, and/or aliphatic at β -position are synthesized single step from substituted non-substituted aryl alkenes. An intramolecular variant also achieved via reaction fluoroarene ω-alkenyl side chain boronate.

Language: Английский

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