Photo‐ and Cobalt‐Catalyzed Synthesis of Heterocycles via Cycloisomerization of Unactivated Olefins

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: Feb. 28, 2024

Abstract We report a general, intramolecular cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and tolerates ethers, esters, protected amines, acetals, pyrazoles, carbamates, arenes. It is amenable to N ‐, O as well C ‐nucleophiles, yielding number different heterocycles including, but not limited to, pyrrolidines, piperidines, oxazolidinones, lactones. Use both benzothiazinoquinoxaline organophotocatalyst Co‐salen catalyst obviates the need for stoichiometric oxidant or reductant. showcase utility protocol in late‐stage drug diversification synthesis several small natural products.

Language: Английский

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Engaging Alkenes in Metallaphotoredox: A Triple Catalytic, Radical Sorting Approach to Olefin-Alcohol Cross-Coupling

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(18), P. 12300 - 12309

Published: April 24, 2024

Metallaphotoredox cross-coupling is a well-established strategy for generating clinically privileged aliphatic scaffolds via single-electron reactivity. Correspondingly, expanding metallaphotoredox to encompass new C(

Language: Английский

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Fe/Thiol Cooperative Hydrogen Atom Transfer Olefin Hydrogenation: Mechanistic Insights That Inform Enantioselective Catalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(25), P. 17296 - 17310

Published: June 14, 2024

Asymmetric hydrogenation of activated olefins using transition metal catalysis is a powerful tool for the synthesis complex molecules, but traditional catalysts have difficulty with enantioselective reduction electron-neutral, electron-rich, and minimally functionalized olefins. Hydrogenation based on radical, metal-catalyzed hydrogen atom transfer (mHAT) mechanisms offers an outstanding opportunity to overcome these difficulties, enabling mild challenging selectivity that complementary hydrogenations H2. Further, mHAT presents asymmetric induction through cooperative (cHAT) chiral thiols. Here, we report insights from mechanistic study iron-catalyzed achiral cHAT reaction leverage deliver stereocontrol Kinetic analysis variation silane structure point hydride iron as likely rate-limiting step. The data indicate selectivity-determining step quenching alkyl radical by thiol, which becomes more potent H donor when coordinated iron(II). resulting iron(III)–thiolate in equilibrium other species, including FeII(acac)2, shown be predominant off-cycle species. enantiodetermining nature thiol trapping enables net commercially available glucose-derived catalyst up 80:20 enantiomeric ratio. To best our knowledge, this first demonstration via mHAT. These findings advance understanding act proof principle development reactions.

Language: Английский

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Photo- and Cobalt-Catalyzed Cycloisomerization of Unsaturated Guanidines, (Iso-)Ureas, and Carbonates

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

We report intramolecular photocatalyzed cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and utilizes guanidines, ureas, isoureas, isothioureas, carbonates to yield several different five-, six-, seven-membered heterocycles. Use benzothiazinoquinoxaline as an organophotocatalyst cobalt–salen catalyst obviates the need for a stoichiometric oxidant or reductant.

Language: Английский

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Manganese-Catalyzed Mukaiyama Hydration Reaction for Undergraduate Organic Chemistry Course

Journal of Chemical Education, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 7, 2025

Language: Английский

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Cobalt-catalyzed radical hydroamination of olefins

Trends in Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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Modifying commodity-relevant unsaturated polymers via Co-catalyzed MHAT

Chem, Journal Year: 2024, Volume and Issue: 10(10), P. 3088 - 3099

Published: June 19, 2024

Language: Английский

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Photoinduced Co/Ni-cocatalyzed Markovnikov hydroarylation of unactivated olefins with aryl bromides

Chemical Science, Journal Year: 2024, Volume and Issue: 15(36), P. 14865 - 14871

Published: Jan. 1, 2024

A novel photoinduced Co/Ni-cocatalyzed Markovnikov hydroarylation of unactivated alkenes with aryl bromides by using proton as a hydrogen source has been developed for the first time.

Language: Английский

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Unveiling the Reactivity of Part Per Million Levels of Cobalt‐Salen Complexes in Hydrosilylation of Ketones

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(46)

Published: June 10, 2024

A series of air-stable cobalt(III)salen complexes Co-1 to Co-4 have been synthesized and employed in the hydrosilylation ketones. Notably, most intricately tailored Co-3 pre-catalyst exhibited exceptional catalytic activity under mild reaction conditions. The developed protocol proceeded with an unusual ppm level (5 ppm) catalyst loading achieved a maximum turnover number (TON) 200,000. wide variety aromatic, aliphatic, heterocyclic ketones encompassing both electron-donating electron-withdrawing substituents were successfully transformed into desired silyl ethers or secondary alcohols moderate excellent yields.

Language: Английский

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CoSalen-Catalyzed Radical Hydrofunctionalization of Unactivated Internal Olefins at Low Catalyst Loading: Method Development, Regioselectivity, and Applications in Post-Polymerization Modification

Published: Feb. 29, 2024

The past two decades witnessed the rapid development of CoSalen-catalyzed hydrofunctionalization reactions, mostly on terminal and conjugation-activated olefins. However, use 1,2-dialkylsubstituted alkenes continues to pose challenges. In this study, we revisit substrate class in context Carreira-type reactions introduce a simple yet effective modification (over 250-fold-increase TON). Near-quantitative yields can be achieved at low catalyst loading, typically 0.05 mol%. key lies inhibiting degradation Salen backbone using molecular sieves. This new protocol facilitates study MHAT regioselectivity type alkenes. We found that allylic electron-negative groups hyperconjugation have profound effects, yielding regioisomeric ratios ranging from 6.5:1 < 1:20. high TON, mild conditions, versatility method further enable its application post-polymerization several olefin-rich, commodity-relevant polymers.

Language: Английский

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