Photoredox/Pyridine N-Oxide Catalyzed Carbohydroxylation and Aminohydroxylation of α-Olefins

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Март 15, 2025

Regioselective carbohydroxylation and aminohydroxylation of α-olefins were developed by a photoredox catalyst pyridine N-oxide. This approach offers the catalytic direct conversion unactivated alkenes to series primary alcohols, including those bearing β-quaternary carbon centers β-amino alcohols. The regioselective difunctionalization is enabled radical addition α-olefin from N-oxy radical, which generated readily available N-oxide via catalyzed single-electron oxidation. A combination experimental computational mechanistic studies was employed lend support for proposed reaction mechanism that proceeds interwoven steps polar substitution. implications this method further demonstrated examples carboetherification, carboesterification, lactone formation.

Язык: Английский

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Electrochemical Cyclization of o-Aminyl Azobenzenes: Roles of Aldehydes in N–N Bond Cleavage

Organic Letters, Год журнала: 2024, Номер 26(30), С. 6324 - 6329

Опубликована: Июль 22, 2024

Direct functionalization of azobenzenes provides an approach to obtaining valuable molecules in synthetic chemistry. However, efficient method for the cleavage N═N bond azobenzenes, which is a key process this transformation, still lacking. We herein disclose electrochemical reduction-induced cyclization with aldehydes via cleavage. This proceeds well absence any transition metals or external chemical oxidants, leading formation N-protected benzimidazoles moderate good yields.

Язык: Английский

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Catalytic Asymmetric Aza-Electrophilic Additions of 1,1-Disubstituted Styrenes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(31), С. 21535 - 21545

Опубликована: Июль 26, 2024

Electrophilic addition of alkenes is a textbook reaction that plays pivotal role in organic chemistry. In the past decades, catalytic asymmetric variants this important type have witnessed great achievements by development novel systems. However, enantioselective aza-electrophilic additions unactivated alkenes, which could provide transformative strategy for preparation synthetically significant nitrogen-containing compounds, still remain formidable challenge. Herein, we developed unprecedented Au(I)/NHC-catalyzed 1,1-disubstituted styrenes utilization readily available dialkyl azodicarboxylates as electrophilic nitrogen sources. Based on approach, series transformations, including [2 + 2] cycloaddition, intermolecular 1,2-oxyamination, and several types intramolecular hydrazination-induced cyclizations, been realized. These transformations previously unattainable platform divergent synthesis hydrazine derivatives, also be converted to other chiral synthons. Experimental computational studies support idea carbocation intermediates are involved pathways.

Язык: Английский

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Direct Synthesis of 2-Hydroxytrifluoroethylacetophenones via Organophotoredox-Mediated Net-Neutral Radical/Polar Crossover

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(16), С. 11682 - 11692

Опубликована: Авг. 1, 2024

Alkene difunctionalization is a very attractive tool in synthetic organic chemistry. Herein, we disclose an operationally and practically simple method to access 2-hydroxytrifluoroethylacetophenones from styrene derivatives via photoredox catalysis. This light-mediated transformation promotes the generation of 1-hydroxy-2,2,2-trifluoroethyl carbon-centered radical as key synthon, which undergoes Giese addition with styrenes followed by Kornblum oxidation process. The presented not only mild cost-effective, but also utilizes photocatalyst DMSO oxidant. Experimental investigations support operative mechanism net-neutral radical/polar crossover.

Язык: Английский

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Moderate Active Hydrogen Generation over a Ni₂P/CoP Heterostructure for One-Step Electrosynthesizing of Azobenzene with High Selectivity

Nano Letters, Год журнала: 2025, Номер 25(2), С. 828 - 836

Опубликована: Янв. 6, 2025

Through hydrogenation and N-N coupling, azobenzene can be produced via highly selective electrocatalytic nitrobenzene reduction, offering a mild, cost-effective, sustainable industrial route. Inspired by the density functional theory calculations, introduction of H* active Ni2P into CoP, which reduces water dissociation energy barrier, optimizes adsorption, moderates key intermediates' is expected to assist its ability for one-step electrosynthesizing azobenzene. A self-supported NiCo@Ni2P/CoP nanorod array electrode was synthesized, featuring NiCo alloy nanoparticles within Ni2P/CoP shell. By virtue thermodynamically optimal heterostructure, along with overall fast electron transport in core-shell integrated electrode, abundant interfacial structure attains great conversion 94.3%, especially prominent selectivity 97.2%, Faradaic efficiency 94.1% at -0.9 V (vs Hg/HgO). High-purity crystals also self-separate under refrigeration postelectrolysis. This work provides an energy-efficient scalable pathway economical preparation hydrogenation.

Язык: Английский

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Cocatalyst-Dependent Divergent Amination of Alkylgold Intermediates with Azodicarboxylates

ACS Catalysis, Год журнала: 2025, Номер unknown, С. 5211 - 5218

Опубликована: Март 12, 2025

The asymmetric electrophilic amination using azodicarboxylates as the N-source for construction of C–N bond has attracted much attention over past decades. However, use in situ formed nucleophilic intermediates, rather than bench-stable reagents, remains elusive and challenging. Herein, we disclose an enantioselective reaction generated alkylgold species with under a gold complex chiral quinine-derived squaramide (QN-SQA) synergetic catalysis, leading to alkylideneoxazolines nitrogen-containing tertiary carbon stereocenter good high yields enantioselectivities. Moreover, starting from same oxazoles incorporating aminomethyl group on 5-position could be obtained by Brønsted acid relay catalysis via alkylideneoxazoline species. This method offers complementary approach through interception With this strategic protocol, further synthetic applications can envisioned catalytic C–C C–X bonds.

Язык: Английский

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Enhanced Pyridine-Oxazoline Ligand-Enabled Pd(II)-Catalyzed Aminoacetoxylation of Alkenes for the Asymmetric Synthesis of Biaryl-Bridged 7-Membered N-Heterocycles and Atropisomers

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Апрель 1, 2025

A new class of binaphthyl unit-enhanced pyridine-oxazoline ligands was developed to promote the Pd-catalyzed enantioselective intramolecular 7-exo aminoacetoxylation unactivated biaryl alkenes. Biaryl-bridged 7-membered N-heterocycles bearing a chiral center were obtained in good yields with excellent enantioselectivities (up 99:1 er). Computational investigations on series biaryl-bridged rings provided insights into rotational barrier potentially unit by substituent effect including heteroatom, protecting group, and center. The kinetic resolution racemic axially biaryls via alkenes has also been achieved, affording previously inaccessible both axis, as well amino alcohols.

Язык: Английский

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Catalyst-Free Direct Olefin Halo-Hydroxylamination: Rapid Syn-thesis of Multifunctional Hydroxylamines (MFHAs) for Structurally Complex Amines and N-Heterocycles

Опубликована: Июнь 4, 2024

Herein, we introduce a novel and powerful alkene difunctionalization process where anomeric amides (e.g., N-halogenated O-activated hydroxylamines) react directly with olefins, without the use of catalysts or additives, to yield corresponding N-haloalkyl hydroxylamines. These multifunctional hydroxylamines (MFHAs), containing both alkyl halide hydroxylamine moieties, are convenient building blocks/electrophilic aminating reagents for synthesis structurally complex N-unprotected secondary amines N-heterocycles. Both activated unactivated alkenes (including cyclic acyclic dienes, enynes) effectively converted difunctionalized derivatives excellent atom economy. The versatility MFHAs was demonstrated through various nitrogen-containing molecules.

Язык: Английский

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Electrochemical N‐Centered Radical‐Triggered Intramolecular N‐N Coupling for the Cyclization of o‐Aminyl Azobenzenes

European Journal of Organic Chemistry, Год журнала: 2024, Номер 27(46)

Опубликована: Авг. 28, 2024

Abstract An electrochemical radical cyclization of o ‐aminyl azobenzenes via N ‐centered generation has been developed for the synthesis benzotriazoles. The bearing a sulfonyl protection on amine readily proceeds in absence any external transition metal catalyst or chemical oxidant, and exhibits good tolerance towards functional groups.

Язык: Английский

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Azocarboxamide-enabled enantioselective regiodivergent unsymmetrical 1,2-diaminations

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Ноя. 26, 2024

Язык: Английский

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