Advances in theE → ZIsomerization of Alkenes Using Small Molecule Photocatalysts

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2650 - 2694

Опубликована: Авг. 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.

Язык: Английский

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Electrocatalytic Radical Dichlorination of Alkenes with Nucleophilic Chlorine Sources

Journal of the American Chemical Society, Год журнала: 2017, Номер 139(43), С. 15548 - 15553

Опубликована: Окт. 8, 2017

We report a Mn-catalyzed electrochemical dichlorination of alkenes with MgCl2 as the chlorine source. This method provides operationally simple, sustainable, and efficient access to variety vicinally dichlorinated compounds. In particular, oxidatively labile functional groups, such alcohols, aldehydes, sulfides, amines, were transformed into desired vicinal dichlorides high chemoselectivity. Mechanistic data are consistent metal-mediated Cl atom transfer predominant pathway enabling dual C–Cl bond formation contradict an alternative involving evolution gas followed by Cl2-mediated electrophilic dichlorination.

Язык: Английский

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Hypervalent iodine(iii) fluorinations of alkenes and diazo compounds: new opportunities in fluorination chemistry

Chemical Society Reviews, Год журнала: 2016, Номер 45(22), С. 6270 - 6288

Опубликована: Янв. 1, 2016

The review gives a timely overview on the fluoro functionalization of alkenes and diazo compounds using hypervalent λ³-iodane chemistry.

Язык: Английский

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Catalytic, Diastereoselective 1,2-Difluorination of Alkenes

Journal of the American Chemical Society, Год журнала: 2016, Номер 138(15), С. 5000 - 5003

Опубликована: Апрель 5, 2016

We describe a direct, catalytic approach to the 1,2-difluorination of alkenes. The method utilizes nucleophilic fluoride source and an oxidant in conjunction with aryl iodide catalyst is applicable alkenes all types substitution patterns. In general, vicinal difluoride products are produced high diastereoselectivities. observed sense stereoinduction implicates anchimeric assistance pathways reactions bearing neighboring Lewis basic functionality.

Язык: Английский

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Catalytic Difluorination of Olefins

Journal of the American Chemical Society, Год журнала: 2016, Номер 138(15), С. 5004 - 5007

Опубликована: Март 15, 2016

Molecular editing with fluorine is a validated strategy for modulating the structure and function of organic systems. In current arsenal catalytic dihalogenation technologies, direct generation vicinal difluoride moiety from simple olefins without prefunctionalization step remains conspicuously absent. Herein we report catalytic, difluorination displaying broad functional group tolerance, using inexpensive p-iodotoluene as catalyst. Preliminary efforts toward development an enantioselective variant are also disclosed.

Язык: Английский

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Three-Component Olefin Dicarbofunctionalization Enabled by Nickel/Photoredox Dual Catalysis

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(51), С. 20069 - 20078

Опубликована: Дек. 13, 2019

An intermolecular, photocatalytic dicarbofunctionalization (DCF) of olefins enabled by the merger Giese-type addition with Ni/photoredox dual catalysis has been realized. Capitalizing on rapid 3° radicals to alkenes and their reluctance toward single electron metalation Ni complexes, regioselective alkylation arylation is possible. This catalytic method not only permits elaborate species be assembled from commodity materials, but also allows quaternary tertiary centers installed in a singular, chemoselective olefin difunctionalization. multicomponent process occurs under exceptionally mild conditions, compatible diverse range functional groups synthetic handles such as pinacolboronate esters. technology was directly applied synthesis an intermediate preclinical candidate (TK-666) its derivatives.

Язык: Английский

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Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations

Science, Год журнала: 2021, Номер 371(6528), С. 507 - 514

Опубликована: Янв. 28, 2021

Vicinal dibromides and dichlorides are important commodity chemicals indispensable synthetic intermediates in modern chemistry that traditionally synthesized using hazardous elemental chlorine bromine. Meanwhile, the environmental persistence of halogenated pollutants necessitates improved approaches to accelerate their remediation. Here, we introduce an electrochemically assisted shuttle (e-shuttle) paradigm for facile scalable interconversion alkenes vicinal dihalides, a class reactions can be used both synthesize useful dihalogenated molecules from simple recycle waste material through retro-dihalogenation. The reaction is demonstrated 1,2-dibromoethane, as well 1,1,1,2-tetrachloroethane or 1,2-dichloroethane, dibrominate dichlorinate, respectively, wide range setup with inexpensive graphite electrodes. Conversely, hexachlorinated persistent pollutant lindane could fully dechlorinated benzene soil samples alkene acceptors.

Язык: Английский

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The Fluorine Gauche Effect: A Brief History

Israel Journal of Chemistry, Год журнала: 2016, Номер 57(1-2), С. 92 - 100

Опубликована: Сен. 20, 2016

Abstract Transforming the fluorine gauche effect from an academic curiosity into a powerful acyclic conformational control strategy has enriched molecular design. This expansive approach to modulating structure proven be particularly valuable in construction of functional small molecules, thereby finding application diverse disciplines, ranging therapeutic medicine enantioselective catalysis. In contrast well‐established arsenal tactics, which conformer populations result minimising nonbonding interactions, (e.g., A 1,3 ‐ or 1,2 ‐strain), is attributable stabilising interactions comprised two components: stereoelectronic and electrostatic. Conformer are partially determined by favourable, hyperconjugative involving proximal electron‐rich σ‐bonds, π‐systems, electron pairs with antibonding orbital C−F σ‐bond: σ→σ*, π→σ*, n→σ*, respectively. Electrostatic, charge‐dipole N + ⋅⋅⋅F δ− ) also play crucial role what often counter‐intuitive conformations. These noncovalent permissible on account low van der Waals radius high electronegativity atom, render this fundamentally important practically structural chemistry. contribution Rosarium Philosophorum honour Prof. Jack David Dunitz FRS, we endeavour delineate, albeit abridged form, evolution fundamental spectroscopic study ubiquitous component physical organic

Язык: Английский

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Unnatural Amino Acid Synthesis Enabled by the Regioselective Cobalt(III)‐Catalyzed Intermolecular Carboamination of Alkenes

Angewandte Chemie International Edition, Год журнала: 2016, Номер 55(48), С. 15166 - 15170

Опубликована: Окт. 27, 2016

Abstract Herein, we report an unprecedented regioselective and entirely atom‐economic cobalt(III)‐catalyzed method for the non‐annulative, intermolecular carboamination of alkenes. The methodology enables direct synthesis unnatural amino acid derivatives proceeds under redox‐neutral conditions with a completely C−C bond C−N formation. Furthermore, this reaction exemplifies inherently different mechanistic behavior Cp*Co III catalyst its Cp*Rh counterpart, especially towards β‐H‐elimination.

Язык: Английский

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Asymmetric three-component olefin dicarbofunctionalization enabled by photoredox and copper dual catalysis

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Март 22, 2021

Abstract The intermolecular three-component alkene vicinal dicarbofunctionalization (DCF) reaction allows installation of two different carbon fragments. Despite extensive investigation into its ionic chemistry, the enantioseletive radical-mediated versions DCF reactions remain largely unexplored. Herein, we report an intermolecular, enantioselective radical olefins enabled by merger addition and cross-coupling using photoredox copper dual catalysis. Key to success this protocol relies on chemoselective acyl cyanoalkyl radicals, generated in situ from redox-active oxime esters a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto alkenes form new radicals. Single electron metalation such newly formed radicals TMSCN-derived L1 Cu(II)(CN) 2 complex leads asymmetric cross-coupling. This process proceeds under mild conditions, tolerates diverse range functionalities synthetic handles, leading valuable optically active β –cyano ketones alkyldinitriles, respectively, highly manner (>60 examples, up 97% ee).

Язык: Английский

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