Biomimetic Dehydrogenative Intermolecular Formal Allylic Amidation of Branched α‐Olefins

Advanced Science, Journal Year: 2024, Volume and Issue: 12(2)

Published: Nov. 18, 2024

Abstract Allylic amide moieties are commonly encountered in natural products and privileged structures pharmaceuticals agrochemicals. Moreover, because allylic can be to converted into an array of high‐value motifs, they have been widely employed organic synthesis. However, the development catalytic systems for intermolecular amidation olefins, particularly branched α ‐olefins, has proven challenging. Here, a biomimetic, synergistic method is reported that combines photoredox, cobalt, Brønsted base catalysis synthesis substituted amides from ‐olefins simple imides without using oxidants. This low‐cost, operationally features broad substrate scope excellent functional group compatibility. it successfully used functionalization several structurally complex molecules demonstrating method's potential utility medicinal chemistry applications. Mechanistic studies revealed C( sp 3 )─N bond formation mediated by nitrogen‐centered radical intermediate, which generated via sequence involving deprotonation single‐electron oxidation.

Language: Английский

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Sequential Photocatalysis for Homologative Diversification of α-Amino Acids to β-Amino Acids Via Phosphonium Ylide Linchpin Strategy

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 12, 2024

β-Amino acids serve as crucial building blocks for a broad range of biologically active molecules and peptides with potential peptidomimetics. While numerous methods have been developed the synthesis β-amino acids, most them require multistep preparation specific reagents substrates, which limits their synthetic practicality. In this regard, homologative transformation abundant readily available α-amino would be an attractive approach acid synthesis. Herein, we disclose development sequential process to provide diverse from derivatives commercially phosphonium ylides via visible light photoredox catalysis. two-step protocol, function bifunctional linchpin: they act carbon nucleophile forge C-C bond in first step carbon-centered radical source modifications scaffold second step. The orthogonal activation these reactivities under mild photocatalytic conditions enables modular three-component assembly access dipeptides high structural diversity.

Language: Английский

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Mechanism, Chemoselectivity, and Stereoselectivity of an NHC-Catalyzed Reaction of Aldehydes and Hydrazones: A DFT Study

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(22), P. 4483 - 4492

Published: May 24, 2024

To elucidate the mechanism and origins of chemo- enantioselectivities reaction between aliphatic aldehydes hydrazones catalyzed by triazolium-derived NHC, density functional theory computations have been performed. According to our calculated results, whole catalytic cycle for formation dihydropyridazinones proceeds via initial nucleophilic addition NHC an aldehyde, followed concerted intramolecular proton transfer C-Cl bond cleavage. Subsequent deprotonation generates enolate intermediate. The intermediate then undergoes 1,4-addition hydrazone construct a new carbon-carbon bond. following ring-closure would lead six-membered ring intermediate, which, upon release affords final product dihydropyridazinone. computation results reveal that is significantly promoted Brønsted acid DIPEA·H

Language: Английский

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Dual N-Heterocyclic Carbene/Photoredox-Catalyzed Coupling of Acyl Fluorides and Alkyl Silanes

ACS Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 17642 - 17653

Published: Nov. 15, 2024

The combination of N-heterocyclic carbene (NHC) organocatalysis with photochemical activation is becoming increasingly established as an approach for conducting radical organic reactions under mild and practical conditions. As comparatively easy to prepare handle compounds, alkyl silanes are attractive substrates chemistry desilylative mesolysis the corresponding cations known be rapid. Here, we report successful application benzyl silane derivatives source radicals in dual NHC/photoredox-catalyzed radical–radical coupling acyl fluorides. Relatively electron-rich reacted smoothly afford ketones generally good yields, while optimization NHC photocatalyst allowed a wider scope including primary substrates. Furthermore, initial experiments revealed that organosilanes bearing N-, O- S-heteroatoms can also serve sources these

Language: Английский

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Stereoselective Aminomethylation of β,β-Disubstituted Enesulfinamides: Asymmetric Construction of Less Accessible Acyclic α,α-Disubstituted α-Aminomethylated Ketimines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 21, 2024

β,β-Disubstituted enesulfinamides undergo stereoselective nucleophilic addition to the formaldehyde imines, in situ formed from tosylmethylcarbamates, affording α-aminomethylated ketimines bearing a challenging acyclic quaternary stereocenter substituted by two sterically and electronically similar groups (e.g., Me Et). The defined geometry of C═C bond enesulfinamides, combined with strong chiral induction offered their sulfinyl group, ensures precise stereocontrol during formation new C-C bond.

Language: Английский

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Development of Ir-cR8-albumin nanomedicine toward the interventional treatment of liver cancer

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: May 23, 2024

Hepatocellular carcinoma is one of the most challenging malignancies with high incidence and mortality rates in world. Digital subtraction angiography (DSA)-guided hepatic arterial infusion standard chemotherapeutic agent oxaliplatin has advantages both precision efficacy, making it an important therapeutic strategy for advanced-stage liver cancer. However, patients undergoing this treatment still face severe systemic toxicity poor tolerability oxaliplatin. In study, we compared a novel albumin nanoparticle-formulated oncolytic peptide Ir-cR8 (Ir-cR8-BSA-NP) orthotropic cancers mouse model by intravenous injection rabbit DSA-guided infusion. The Ir-cR8, containing cationic octa-arginine ring hydrophobic domain, was found to interact bovine serum further assemble into spherical nanoparticles average diameter 150 nm. Such opsonisation significantly increases stability reduces its haemolytic toxicity. vivo experiments mice showed that administration Ir-cR8-BSA-NP had excellent inhibitory effects on H22 orthotopic tumours reduced animals than Furthermore, VX2 cancer model, or administered artery under DSA guidance, followed PET/CT assessment efficacy. results outperformed reducing tumour size. Thus, study demonstrated combined membrane-active nanomedicine precise drug delivery enabled technology interventional

Language: Английский

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Aerobic Oxysulfonylation of Olefins Using N-Sulfonylaminophthalimides as Sulfonyl Radical Precursors

Organic Letters, Journal Year: 2024, Volume and Issue: 26(31), P. 6647 - 6651

Published: July 29, 2024

Readily accessible N-sulfonylaminophthalimides were developed to be efficient sulfonyl radical precursors upon being treated with a base/oxidant under mild conditions. The method was applied the oxysulfonylation of olefins, providing β-ketosulfones and isobenzofurans stereoselectively. On basis control experiments, density functional theory calculations, literature, plausible mechanism proposed. findings offered chance develop novel based on diversely substituted N-aminophthalimides, which might establish universal approach for generation various radicals.

Language: Английский

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Tandem N-Heterocyclic Carbene/Photocatalysis Approach for the Synthesis of Amino Esters

Synfacts, Journal Year: 2023, Volume and Issue: 20(01), P. 0077 - 0077

Published: Dec. 8, 2023

Key words photocatalysis - N-heterocyclic carbene amino esters imidyl radicals

Language: Английский

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