An electrocatalytic approach to access structurally significant azabicyclic scaffolds from -allyl enamine carboxylates is illustrated. This metal-free method functions exclusively with a catalytic amount of iodide, strategically employed to electrochemically generate a reactive hypervalent iodine species, which facilitates the cascade bicyclization processes with enhanced precision and efficiency. Excellent functional group compatibility was observed, enabling the synthesis of a series of azabicycle derivatives. Detailed mechanistic and electrochemical studies enhance the comprehension of the reaction sequence.
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http://dx.doi.org/10.1021/acs.orglett.4c00756 | DOI Listing |
J Org Chem
November 2024
Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, 75005 Paris, France.
Despite conceptual breakthroughs in dual photoredox- and nickel-catalyzed arylation of radicals, the approach remains largely limited to localized C-centered radicals. Here, we extend it to allylic radicals, focusing on -allyl heterocycles. Using [Ir(dF(CF)ppy)(dtbbpy)]PF and NiCl(dtbbpy) under visible light, we achieve regioselective γ-amino radical arylation, yielding enamines in good yields.
View Article and Find Full Text PDFChem Sci
October 2024
Equipe Synthèse Organique et Phytochimie, Institut de Chimie, CNRS-UdS UMR 7177, 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
Herein, we report the first visible-light-induced strategy for the rapid synthesis of densely functionalized α- and γ-phosphorylated β-sulfonyl enamines in a regio- and stereoselective manner from -sulfonyl allenamides and H-phosphine oxides. The transformation displays a broad substrate scope, while operating at room temperature under photocatalyst- and additive-free conditions. In this atom-economical process, either terminal or substituted -sulfonyl allenamides trigger an unprecedented -to- [1,3]-sulfonyl shift, relying on a dual radical allyl resonance and α-heteroatom effect in its triplet excited state.
View Article and Find Full Text PDFJ Org Chem
October 2024
Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Lu, Shanghai 200444, China.
We describe an allylation reaction between 2-(2-azaaryl)acetic acids and allylic electrophiles catalyzed synergistically by a dual system consisting of borinic acid and a Pd complex under mild conditions. The decarboxylative allylation proceeds via a boron-bound enamine intermediate, which then interacts with a π-allylpalladium intermediate from the allylic electrophile. High yields of diallylation products highlight the method's efficiency.
View Article and Find Full Text PDFOrg Lett
August 2024
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, School of Environment, Henan Normal University, Xinxiang, Henan 453007, China.
Presented herein is a novel synthesis of indenone-fused pyran derivatives via the cascade reactions of aryl enaminones with cyclopropenones. The formation of products involves a one-pot cascade procedure consisting of aryl C-H bond and enamine C-H bond functionalization along with C-C bond cleavage of cyclopropenone and 1,3-rearrangement of the in situ-formed allylic alcohol moiety followed by intramolecular O-nucleophilic addition and MeNH elimination. To our knowledge, this is the first synthesis of indenone-fused pyran derivatives via simultaneous formation of both indenone and pyran scaffolds through concurrent unsymmetrical relay C-H bond activation and double C-C/C-O bond formation.
View Article and Find Full Text PDFChem Soc Rev
July 2024
Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
The asymmetric catalytic synthesis of 1,2-diamines has received considerable interest, especially in the last ten years, due to their presence in biologically active compounds and their applications for the development of synthetic building blocks, chiral ligands and organocatalysts. Synthetic strategies based on C-N bond-forming reactions involve mainly (a) ring opening of aziridines and azabenzonorbornadienes, (b) hydroamination of allylic amines, (c) hydroamination of enamines and (d) diamination of olefins. In the case of C-C bond-forming reactions are included (a) the aza-Mannich reaction of imino esters, imino nitriles, azlactones, isocyano acetates, and isothiocyanates with imines, (b) the aza-Henry reaction of nitroalkanes with imines, (c) imine-imine coupling reactions, and (d) reductive coupling of enamines with imines, and (e) [3+2] cycloaddition with imines.
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