Nickel-Catalyzed Dicarbofunctionalization of Alkenes

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(15), P. 8542 - 8556

Published: July 2, 2020

1,2-Dicarbofunctionalization of alkenes has emerged as an efficient synthetic strategy for preparing substituted molecules by coupling readily available with electrophiles and/or nucleophiles. Nickel complexes serve effective catalysts owing to their tendency undergo facile oxidative addition and slow β-hydride elimination, capability access both two-electron radical pathways. Two-component alkene functionalization reactions have achieved high chemo-, regio-, stereoselectivities tethering one the partners substrate. Three-component reactions, however, often incorporate directing groups control selectivity. Only a few examples directing-group-free difunctionalizations unactivated been reported. Therefore, great opportunities exist development three-component difunctionalization broad substrate scopes tunable stereoselectivities.

Language: Английский

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The High Chemofidelity of Metal-Catalyzed Hydrogen Atom Transfer

Accounts of Chemical Research, Journal Year: 2018, Volume and Issue: 51(11), P. 2628 - 2640

Published: Nov. 8, 2018

ConspectusThe implementation of any chemical reaction in a structurally complex setting (King, S. M. J. Org. Chem. 2014, 79, 8937) confronts defined barriers: steric environment, functional group reactivity, product instability, and through-bond electronics. However, there are also practical barriers. Late-stage reactions conducted on small quantities material run inevitably at lower than optimal concentrations. Access to late-stage limits extensive optimization. Impurities from past can interfere, especially with catalytic reactions. Therefore, which one rely the front lines synthesis campaign emerge crucible total as robust, dependable, widely applied. Trost conceptualized "chemoselectivity" reagent's selective or reactive site preference others (Trost, B. Science 1983, 219, 245). Chemoselectivity tolerance be evaluated quickly using robustness screens (Collins, K. D. Nat. 2013, 5, 597). A may characterized by its "chemofidelity", that is, reliable molecular context. For example, ketone reduction an electride (dissolving metal conditions) exhibits high chemofidelity but low chemoselectivity: it usually works, many other groups reduced similar rates. Conversely, alkene coordination chemistry effected π Lewis acids exhibit chemoselectivity 245) chemofidelity: highly for alkenes sensitive substitution pattern (Larionov, E. Commun. 50, 9816). In contrast, undergo reliable, diverse hydrogen atom transfer hydrides generate carbon-centered radicals. Although potential applications this chemistry, tolerance, rates, ease execution have led rapid deployment campaigns. Its success derives chemofidelity, dependable reactivity environments patterns. Metal hydride H (MHAT) convert diverse, simple building blocks more stereochemically functionally dense products (Crossley, W. Rev. 2016, 116, 8912). When is returned metal, MHAT considered radical equivalent Brønsted acid catalysis—itself broad paradigm. This Account summarizes our group's contributions method development, reagent discovery, mechanistic interrogation. Our earliest contribution area—a stepwise hydrogenation chemofidelity—has found application problems. More recently, we reported first examples dual-catalytic cross-couplings merger cycles nickel catalysis. With time, anticipate will become staple synthesis.

Language: Английский

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Synergistic Dual Transition Metal Catalysis

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(24), P. 13382 - 13433

Published: Nov. 29, 2020

Synergistic catalysis, a type of plural catalysis which utilizes at least two different catalysts to enable reaction between separately activated substrates, has unlocked plethora previously unattainable transformations and novel chemical reactivity. Despite the appreciable utility synergistic specific examples involving transition metals have been limited, as ensuring judicious choice parameters prevent deactivation catalysts, undesirable monocatalytic event(s) leading side products, or premature termination other potentially troublesome outcomes present formidable challenge. Excluding those driven by photocatalytic mechanisms, this review will highlight reported reactions that make use simultaneous catalytic cycles metal catalysts.

Language: Английский

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Fsp3: A new parameter for drug-likeness

Drug Discovery Today, Journal Year: 2020, Volume and Issue: 25(10), P. 1839 - 1845

Published: July 24, 2020

Language: Английский

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Catalytic hydrogen atom transfer to alkenes: a roadmap for metal hydrides and radicals

Chemical Science, Journal Year: 2020, Volume and Issue: 11(46), P. 12401 - 12422

Published: Jan. 1, 2020

Hydrogen atom transfer from metal hydrides to alkenes appears underlie widely used catalytic methods – the mechanistic implications are fascinating.

Language: Английский

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Ni-Catalyzed Reductive Coupling of Electron-Rich Aryl Iodides with Tertiary Alkyl Halides

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(43), P. 14490 - 14497

Published: Oct. 8, 2018

This work illustrates the reductive coupling of electron-rich aryl halides with tertiary alkyl under Ni-catalyzed cross-electrophile conditions, which offers an efficient protocol for construction all carbon quaternary stereogenic centers. The mild and easy-to-operate reaction tolerates a wide range functional groups. utility this method is manifested by preparation cyclotryptamine derivatives, wherein successful incorporation 7-indolyl moieties particular interest as numerous naturally occurring products are composed these key scaffolds. DFT calculations have been carried out to investigate proposed radical chain double oxidative addition pathways, provide useful mechanistic insights into part that takes place in solution.

Language: Английский

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Zn-Mediated Fragmentation of Tertiary Alkyl Oxalates Enabling Formation of Alkylated and Arylated Quaternary Carbon Centers

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 141(2), P. 820 - 824

Published: Dec. 20, 2018

Zn-mediated reduction of readily accessible dialkyl oxalates derived from tertiary alcohols provides an efficient approach to C–O bond fragmentation and alkyl radical formation. With MgCl2 as the indispensable additive Ni promoter, trapping with activated alkenes aryl–Ni intermediates allows for generation alkylated arylated all-carbon quaternary centers.

Language: Английский

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On the Nature of C(sp³)–C(sp²) Bond Formation in Nickel-Catalyzed Tertiary Radical Cross-Couplings: A Case Study of Ni/Photoredox Catalytic Cross-Coupling of Alkyl Radicals and Aryl Halides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(15), P. 7225 - 7234

Published: March 20, 2020

The merger of photoredox and nickel catalysis has enabled the construction quaternary centers. However, mechanism, role ligand, effect spin state for this transformation related Ni-catalyzed cross-couplings involving tertiary alkyl radicals in combination with bipyridine diketonate ligands remain unknown. Several mechanisms have been proposed, all invoking a key Ni(III) species prior to undergoing irreversible inner-sphere reductive elimination. In work, we used open-shell dispersion-corrected DFT calculations, quasi-classical dynamics experiments study detail mechanism carbon–carbon bond formation Ni bipyridine- diketonate-based catalytic systems. These calculations revealed that access high states (e.g., triplet tetrahedral Ni(II) species) is critical effective radical cross-coupling radicals. Further, these disparate C–C formation. Specifically, contrary neutral Ni-bipyridyl system, lead directly corresponding products via an outer-sphere elimination step from intermediates. Implications design new transformations are discussed.

Language: Английский

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Nickel-catalyzed formation of quaternary carbon centers using tertiary alkyl electrophiles

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(6), P. 4162 - 4184

Published: Jan. 1, 2021

This review provides a comprehensive summary of recent advances in nickel-catalyzed reactions employing tertiary alkyl electrophiles for the construction quaternary carbon centers.

Language: Английский

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Nickel-Catalyzed Enantioconvergent Reductive Hydroalkylation of Olefins with α-Heteroatom Phosphorus or Sulfur Alkyl Electrophiles

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 142(1), P. 214 - 221

Published: Dec. 15, 2019

Substantial advances in enantioconvergent C(sp3)–C(sp3) bond formation reactions have been made recent years through the use of transition-metal-catalyzed cross-coupling racemic secondary alkyl electrophiles with organometallic reagents. Herein, we report a general process for asymmetric construction alkyl–alkyl bonds adjacent to heteroatoms, namely, nickel-catalyzed reductive hydroalkylation olefins α-heteroatom phosphorus or sulfur electrophiles. Including readily available olefins, this reaction has considerable advantages, such as mild conditions, broad substrate scope, and good functional group compatibility, making it desirable alternative traditional electrophile–nucleophile reactions.

Language: Английский

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