We herein disclose a novel palladium-catalyzed 1,2-alkynylarylation of vinyl arenes using haloalkynes and arylboronic acids as coupling partners. This reaction is characterized by broad substrate scope, controllable reaction sequence, and excellent chemo- and regioselectivities. Mechanistic investigations suggest that the reaction is initiated by regioselective insertion of vinyl arenes into the alkynyl-Pd(II) species, and the silver salt is crucial for this transformation, serving as both the Lewis acid and halide scavenger. This protocol provides efficient access to new carbon skeletons, which are embedded in the key biologically active motifs.
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http://dx.doi.org/10.1021/acs.orglett.4c00051 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
The azidofunctionalization of alkenes under mild conditions using commercially available starting materials and easily accessible reagents is reported based on a radical-polar crossover strategy. A broad range of alkenes, including vinyl arenes, enamides, enol ethers, vinyl sulfides, and dehydroamino esters, were regioselectively functionalized with an azide and nucleophiles such as azoles, carboxylic acids, alcohols, phosphoric acids, oximes, and phenols. The method led to a more efficient synthesis of 1,2-azidofunctionalized pharmaceutical intermediates when compared to previous approaches, resulting in both reduction of step count and increase in overall yield.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Axially chiral tetrasubstituted alkenes are of increasing value and interest in chemistry-related areas. However, their catalytic asymmetric synthesis remains elusive, owing to the high steric repulsion and relatively low conformational stability. Herein, we disclose the straightforward construction of atropisomeric tetrasubstituted alkenes by effective enantiocontrol in a reaction with vinyl cation intermediates.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Two T-shaped 14-electron rhodium complexes 2 a and 2 b, "framed" and thus stabilized by PNP pincer ligands have been synthesized. The bis(t-butyl)phosphine derived PNP-rhodium complex 2 a was isolated from pentane as the more stable cyclometalated Rh(III) hydrido complex and found to be in equilibrium with the T-shaped 14e Rh(I) complex 2 aT which itself could be directly crystallized upon change of the solvent. The cyclometallation is suppressed using an adamantyl substituted PNP ligand to give the analogous T-shaped Rh(I) species 2 b, stabilized through an agostic interaction with one of the adamantyl C-Hs.
View Article and Find Full Text PDFNat Commun
October 2024
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
The asymmetric Büchner reaction and related arene cyclopropanations represent one type of the powerful methods for enantioselective dearomatization. However, examples of asymmetric Büchner reactions via a non-diazo approach are quite scarce, and the related arene cyclopropanation based on alkynes has not been reported. Herein, we disclose an asymmetric Büchner reaction and the related arene cyclopropanation by copper-catalyzed controllable cyclization of N-propargyl ynamides via vinyl cation intermediates, leading to chiral tricycle-fused cycloheptatrienes and benzonorcaradienes in high yields and enantioselectivities.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
Department of Applied Chemistry and Bioscience, Chitose Institute of Science and Technology, Chitose, 066-8655, Japan.
The reaction of -stannylated propargyl esters in the presence of a cationic gold(I) catalyst affords vinylidenecyclopropane derivatives as a mixture of diastereomers. The -geometry of the alkenes is almost entirely retained in the product. DFT calculations suggest the involvement of the gold(I)-stabilized propargyl cation as a resonance form of gold(I)-coordinated allenylidene species.
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