Synthesis of Atropisomeric Hydrazides by One‐Pot Sequential Enantio‐ and Diastereoselective Catalysis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(42)

Published: Aug. 29, 2022

The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol. This strategy is based on one-pot sequence two organocatalytic cycles featuring the enamine amination branched aldehydes followed by nitrogen alkylation under phase-transfer conditions. resulting axially chiral were obtained directly from commercially available reagents in high yields with good stereocontrol. permutation organocatalysts allowed easy access to all stereoisomers, enabling stereodivergent approach enantioenriched hydrazides.

Language: Английский

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Accelerated Direct Hydroxylation of Aryl Chlorides with Water to Phenols via the Proximity Effect in a Heterogeneous Metallaphotocatalyst

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(10), P. 6068 - 6080

Published: May 6, 2022

The proximity of different active sites in multi-catalytic systems is crucial influencing the catalytic reactions, that is, to occur or be accelerated. Here, we reported a heterogeneous metallaphotocatalyst prepared by embedding Ni(II) species photosensitive covalent organic framework (COF). A concerted triad behavior executed electrons, holes, and Ni triggered dramatic enhancement activation aryl chlorides with water phenols. It demonstrated 50-fold increment its activity when compared homogeneous analogy, for example, Ni(BPDA)Br2. Also, it was able efficiently activate variety corresponding phenols moderate high yields. Interestingly, effective even base-sensitive substituents chlorobenzene bearing NH NH2 groups. On basis detailed experiments, photoactive COF facilitates rapid electron transfer produce Ni(I) oxidative addition. Meanwhile, photogenerated holes oxidized hydroxyl radical, which then attacked Ni(III) intermediates complete cycle.

Language: Английский

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C–C Bond Forming Reactions Enabled by Vitamin B₁₂─Opportunities and Challenges

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(11), P. 6517 - 6531

Published: May 17, 2022

Cobalt not only is an essential micronutrient for mammals but also marks itself as important in organic synthesis, especially the field of catalysis. Various useful reactions, such alkene hydroformylation, hydrogenation, heterofunctionalizations carbon–carbon double bonds, C–H activation, and cross-coupling have been realized with aid this metal. At same time, cobalt deserves special attention a catalyst radical processes; fact, form vitamin B12, it was designed by Nature reversible carrier radicals. Since molecule native Co-complex, very attractive development sustainable transformations, has already demonstrated that B12 its derivatives mediate numerous reactions found applications both construction complex molecules degradation polyhalogenated pollutants. However, Perspective, we focus readers' on C–C bond forming catalyzed which are particularly tool synthesis greener manner. We ponder over challenges remain to be addressed solutions expected come.

Language: Английский

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Recent developments in one-pot stepwise synthesis (OPSS) of small molecules

iScience, Journal Year: 2022, Volume and Issue: 25(9), P. 105005 - 105005

Published: Aug. 28, 2022

One-pot synthesis is an active topic in organic chemistry due to its intrinsic advantages of simple operation, high mass efficiency, low cost, and less amount waste disposal. Among three kinds one-pot syntheses, 1) cascade reactions, 2) multicomponent reactions (MCRs), 3) stepwise (OPSS), OPSS could be more flexible practical since it carried out stepwisely have variable reaction conditions for different steps. This perspective article uses selected examples highlight the recent development involving cyclization, cycloaddition, rearrangement, catalytic heterocyclic scaffolds, asymmetric molecules, natural products, bioactive compounds.

Language: Английский

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One-Metal/Two-Ligand for Dual Activation Tandem Catalysis: Photoinduced Cu-Catalyzed Anti-hydroboration of Alkynes

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(28), P. 13006 - 13017

Published: July 5, 2022

A dual catalyst system based on ligand exchange of two diphosphine ligands possessing different properties in a copper complex has been devised to merge metal- and photocatalytic activation modes. This strategy applied the formal anti-hydroboration activated internal alkynes via tandem sequence which Cu/Xantphos catalyzes B2pin2-syn-hydroboration alkyne whereas Cu/BINAP serves as photocatalyst for visible light-mediated isomerization resulting alkenyl boronic ester. Photochemical studies by means UV–vis absorption, steady-state time-resolved fluorescence, transient absorption spectroscopy have allowed characterizing photoactive species reaction its interaction with intermediate syn-alkenyl ester through energy transfer from triplet excited state catalyst. In addition, mechanistic shed light into speciation interplay between catalytic cycles critical success factors.

Language: Английский

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