De Novo Synthesis of 2,2′-Bipyridines and Related Bis-azines via Cascade Coupling and Double Pyridannulation of Isocyanides

Organic Letters, Journal Year: 2024, Volume and Issue: 26(23), P. 5043 - 5048

Published: June 6, 2024

Herein, we present a new and general protocol for the assembly of 2,2′-bipyridyls from nonpyridine substrates without using any metal catalysts or organometallic reagents. The process starts coupling two 1,3-dienyl isocyanides followed by 6π-electrocyclization/aromatization cascade featuring simultaneous formation pyridine rings in single operation. Notably, this strategy is also applicable to construction nonsymmetrical 2-(2-pyridyl)-quinolines/-quinoxalines. Furthermore, aggregation-induced emission (AIE) characteristics endow our approach with great potential biorelevant fields.

Language: Английский

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Chemoselective Trimerization of Isocyanides: De Novo Synthesis of 2-Indole-Substituted Quinolines and Pyridines

Organic Letters, Journal Year: 2021, Volume and Issue: 24(1), P. 105 - 109

Published: Dec. 10, 2021

A catalyst-free chemoselective trimerization reaction of readily available isocyanides is described. This domino provides facile access to a wide range 2-(indol-2-yl)-quinolines and 2-(indol-2-yl)-pyridines in moderate excellent yields. "head head" heterodimerization two proposed as the key step this reaction.

Language: Английский

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Isocyanide Heterodimerization-Triggered Three-Component Reaction: Diversity-Oriented Synthesis of Quinoxalines

Organic Letters, Journal Year: 2023, Volume and Issue: 25(13), P. 2366 - 2371

Published: March 29, 2023

Known isocyanide-based multicomponent reactions (IMCRs) are usually triggered by addition of the isocyano group to strong electrophilic component. We herein report a new three-component reaction, in which an unprecedented quinoxaline-based zwitterionic intermediate is generated from chemoselective heterodimerization weak ortho-diisocyanoarenes and common isocyanides. This reactive zwitterion could react situ with various trapping agents furnish range structurally diverse quinoxalines.

Language: Английский

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Molecular Rearrangements

Organic Reaction Mechanisms/Organic reaction mechanisms, Journal Year: 2024, Volume and Issue: unknown, P. 433 - 505

Published: March 15, 2024

A blue-light-induced [2,3]-sigmatropic rearrangement of sulfonium ylides has been reported from donor/acceptor diazoalkanes and propargyl sulfides to give functionalized allenes is considered occur via singlet carbene intermediates. mechanism, named maleimide-assisted cycloaromatization, trigger the reactivity acyclic enediynes by a cascade 1,3-proton transfer processes enable undergo cycloaromatization. Computational studies have gain insights into potential energy surfaces competing Lewis-acid catalyzed carbonyl-ene, Prins, carbonyl-olefin metathesis reactions. on origin enantioselectivity in semipinacol vinylogous alpha-ketol cocatalyzed cinchona-based primary amine Bronsted acids indicate reaction proceeds complexation, nucleophilic addition, dehydration, carbon atom migration, enamine–imine tautomerization, imine hydrolysis, Walden inversion.

Language: Английский

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Ligand‐Promoted Catalyzed Reactions

Organic Reaction Mechanisms/Organic reaction mechanisms, Journal Year: 2024, Volume and Issue: unknown, P. 507 - 540

Published: March 15, 2024

General aspects of organometallic catalysis during the period covered in this chapter are critically reviewed elsewhere, highlighting important advances in: TM for C—X bonds formation; performance specific ligands; use cost-effective TMs; Heck-type reactions; TM-catalyzed decarboxylative couplings; transformation some functionalities or substrates using catalysis; migration catalytic process; and biocatalysis involving radical intermediates. Density-functional theory calculations revealed that, after transmetalation with boronic acid, different oxidative addition modes racemic substrate play, leading to a dynamic kinetic asymmetric transformation. Spectroscopic experiments suggested Cu(I) carboxylate as active intermediate aerobic thiolation benzoic acids.

Language: Английский

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Oxidation and Reduction

Organic Reaction Mechanisms/Organic reaction mechanisms, Journal Year: 2024, Volume and Issue: unknown, P. 65 - 139

Published: March 15, 2024

N,N-Dialkyl aniline and aminonaphthalenes undergo oxidative cross-coupling with phenols naphthols using a Cr-salen catalyst (1) under aerobic conditions. A mechanism involving an outer-sphere oxidation of the aniline/aminonaphthalene partner, followed by nucleophilic attack phenol/naphthol has been suggested. This chapter also includes work carried out in fields nitration alkane, alkene, alkyne, aromatic compounds, nitrosylation, sequential nitrosylation reactions TBN as source oxygen nitrogen. Recent applications porphyrin derivatives photocatalysts organic synthesis, both SET energy transfer mechanistic approaches are reviewed. Catalytic electrochemical powerful tool for constructing heterocycles, being gentler environmentally friendly. Progress C–H functionalization cations transition metal-mediated/catalyzed alkylation, arylation, annulation, photoinduced is

Language: Английский

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Radical Reactions

Organic Reaction Mechanisms/Organic reaction mechanisms, Journal Year: 2024, Volume and Issue: unknown, P. 541 - 597

Published: March 15, 2024

A review of photocatalytic strategies, involving radical intermediates importance in organic synthesis, has appeared. The fact that cycles are composed three steps, namely excitation, quenching, and finally restoration, is highlighted. a particular emphasis on the restoration step, exploring how deactivated form catalyst converted back into original state, which permits cycle to start over again. It classifies processes according what species responsible for such as substrate, an intermediate, or sacrificial agent. stereoselective bromoboration acetylene with boron tribromide investigated. mechanism was studied by experiments calculations, besides syn-addition (proceeding via four-membered transition state) polar anti-addition postulated.

Language: Английский

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