Catalytic, asymmetric difluorination of alkenes to generate difluoromethylated stereocenters

Science, Journal Year: 2016, Volume and Issue: 353(6294), P. 51 - 54

Published: July 1, 2016

Difluoromethyl groups possess specific steric and electronic properties that invite their use as chemically inert surrogates of alcohols, thiols, other polar functional important in a wide assortment molecular recognition processes. We report here method for the catalytic, asymmetric, migratory geminal difluorination β-substituted styrenes to access variety products bearing difluoromethylated tertiary or quaternary stereocenters. The reaction uses commercially available reagents ( m -chloroperbenzoic acid hydrogen fluoride pyridine) simple chiral aryl iodide catalyst is carried out readily on gram scale. Substituent effects temperature-dependent variations enantioselectivity suggest cation-π interactions play an role stereodifferentiation by catalyst.

Language: Английский

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Transition‐Metal‐Catalyzed Three‐Component Difunctionalizations of Alkenes

Chemistry - An Asian Journal, Journal Year: 2018, Volume and Issue: 13(17), P. 2277 - 2291

Published: June 13, 2018

Abstract Three‐component reactions can directly convert three reactants into the desired products in one pot and thus greatly shorten synthetic path. Recently, transition‐metal catalysis has been applied difunctionalization of alkenes remarkable progress achieved to facilitate construction a wide range functional molecules with high atom‐ step‐economic efficiency. This Focus Review highlights recent advances this field.

Language: Английский

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Selective Arene Hydrogenation for Direct Access to Saturated Carbo‐ and Heterocycles

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(31), P. 10460 - 10476

Published: Jan. 31, 2019

Arene hydrogenation provides direct access to saturated carbo- and heterocycles thus its strategic application may be used shorten synthetic routes. This powerful transformation is widely applied in industry expected facilitate major breakthroughs the sciences. The ability overcome aromaticity while controlling diastereo-, enantio-, chemoselectivity central use of preparation complex molecules. In general, multisubstituted arenes yields predominantly cis isomer. Enantiocontrol imparted by chiral auxiliaries, Brønsted acids, or transition-metal catalysts. Recent studies have demonstrated that highly chemoselective transformations are possible. Such methods underlying strategies reviewed herein, with an emphasis on synthetically useful examples employ readily available

Language: Английский

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

Chemical Society Reviews, Journal Year: 2016, Volume and Issue: 45(22), P. 6270 - 6288

Published: Jan. 1, 2016

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

Language: Английский

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Positional and Geometrical Isomerisation of Alkenes: The Pinnacle of Atom Economy

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(39), P. 13654 - 13664

Published: June 25, 2019

Strategies to achieve spatiotemporal regulation of pre-existing alkenes via external stimuli are essential given the ubiquity feedstock olefins in chemistry and their downstream applications. Mirroring 1-0 switch that underpins mammalian vision through selective geometric isomerisation retinal, strategies manipulate 2D space by both positional chemical, thermal light-driven processes being intensively pursued. This minireview highlights current state art activating achieving directionality these fundamental chemical transformations.

Language: Английский

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Catalytic Asymmetric Diamination of Styrenes

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(12), P. 4354 - 4357

Published: March 9, 2017

An enantioselective catalytic vicinal diamination of styrenes is reported, which proceeds under entirely intermolecular reaction control. It relies on a chirally modified aryliodine(I) catalyst and within an iodine(I/III) manifold with conventional 3-chloroperbenzoic acid as terminal oxidant. environmentally benign solvent combination not only adds to the attractiveness process but also slows down rate undesired background reaction. A total 30 examples are presented, consistently provide high enantiomeric excesses in range 91–98%.

Language: Английский

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The Fluorine Gauche Effect: A Brief History

Israel Journal of Chemistry, Journal Year: 2016, Volume and Issue: 57(1-2), P. 92 - 100

Published: Sept. 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

Language: Английский

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Recent Advances in the Intermolecular Oxidative Difunctionalization of Alkenes

The Chemical Record, Journal Year: 2018, Volume and Issue: 19(2-3), P. 440 - 451

Published: July 22, 2018

Abstract Functionalization of alkenes has been well investigated by chemists, thus it extensively applied in organic synthesis and industries. In the past few decades, transition‐metal, such as palladium, rhodium, gold, iridium, copper iron, catalyzed functionalization reactions have significantly developed played vital roles synthesis. The difunctionalization are appealing an important alternative to traditional approaches for construction useful carbon centers, particularly quaternary which commonly existed structural motifs numerous natural products, pharmaceuticals, biologically active molecules. This account will summarize our recent advances intermolecular alkenes, also highlight scope limitations mechanisms these reactions. general, this starting from dicarbofunctionalization be discussed. Then carboheterofunctionalization intensively reviewed, diheterofunctionalization highlighted.

Language: Английский

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Fluorination of arylboronic esters enabled by bismuth redox catalysis

Science, Journal Year: 2020, Volume and Issue: 367(6475), P. 313 - 317

Published: Jan. 17, 2020

Teaching bismuth to make and break bonds One major reason why transition metals are good catalysts is that they can shuttle between oxidation states. This flexibility lets them slide in out of chemical bonds; so, for instance, snip a bond carbon boron then stitch carbonfluorine its place. Planas et al. now report also orchestrate such bond-swapping events. They implement fully catalytic cycle fluorination aryl boronates, which hops +3 +5 Science , this issue p. 313

Language: Английский

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Chiral Hypervalent Iodines: Active Players in Asymmetric Synthesis

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(24), P. 12033 - 12088

Published: Nov. 19, 2019

Asymmetric organocatalytic oxidations have been witnessed to an impressive development in the last years thanks establishment of important chiral hypervalent iodines(III/V). Many different approaches involving both stoichiometric and catalytic versions provided a fundamental advance this area within asymmetric synthesis. The easily handing, nontoxic, mild, environmentally friendly (green oxidants), high stability that are features these reagents applied many reactions also allowed exploring further unprecedented enantioselective transformations. intention present review is thus highlight as whole utilized up date prepare iodines(III/V), well their reactivity comprehensive manner.

Language: Английский

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