Palladium-Catalyzed Oxygenative Cross-Coupling of Ynamides and Benzyl Bromides by Carbene Migratory Insertion
作者:Yunpeng Gao、Guojiao Wu、Qi Zhou、Jianbo Wang
DOI:10.1002/anie.201712795
日期:2018.3.1
A palladium‐catalyzed oxygenative cross‐coupling of ynamides and benzyl bromides has been developed. After subsequent hydrogenation, α,α‐disubstituted amide derivatives were obtained in good yields. Migratory insertion of α‐oxo palladium carbene species, generated by intermolecular oxidation, is proposed as the key step in this reaction. The study demonstrates the potential of ynamides to serve as
An efficient approach toward formation of polycyclic coumarin derivatives via carbocation-initiated [4+2] cycloaddition and atom-economical photo-irradiated cyclization
Facile carbocation-initiated [4 + 2] cycloaddition of o-anisole-substituted propargyl silyl ethers and ynamides led to the formation of 4-vinylcoumarins. Subsequent intramolecular cyclization of 3-aryl-4-vinylcoumarins afforded polycyclic coumarin derivatives 11,12-dihydronaphtho[1,2-c]chromen-5-ones in...
Palladium‐Catalyzed Silylcyanation of Ynamides: Regio‐ and Stereoselective Access to Tetrasubstituted 3‐Silyl‐2‐Aminoacrylonitriles
作者:Pierre Hansjacob、Frédéric R. Leroux、Vincent Gandon、Morgan Donnard
DOI:10.1002/anie.202200204
日期:2022.3.28
Tetrasubstituted 2-aminoacrylonitriles (α-enaminonitriles) are underinvestigated building blocks due to the lack of methodologies to synthesize them in a controlled manner. A general access to these valuable scaffolds accompanied by mechanistic investigations and DFT calculations is described. This highly regio- and stereoselective strategy relies on the use of the first intermolecular silylcyanation
Efficient and Divergent Synthesis of α‐Halogenated Amides and Esters by Double Electrophilic Activation of Ynamides
作者:Pierre Thilmany、Gwilherm Evano
DOI:10.1002/anie.201911722
日期:2020.1.2
An efficient and modular entry to α-halogenated amides and esters is reported. This reaction is based on an underestimated double electrophilicactivation of ynamides sequentially involving highly reactive activated keteniminium and iminium ions. Upon simple reaction with HCl and an electrophilic halogenation reagent in the presence of water or an alcohol, a broad range of ynamides can be transformed
Lewis acid catalyzed [2+2] cycloaddition of ynamides and propargyl silyl ethers: synthesis of alkylidenecyclobutenones and their reactivity in ring-opening and ring expansion
A family of four-membered enones, polysubstituted alkylidenecyclobutenones, were easily prepared by the Lewisacidcatalyzed formal [2+2] cycloaddition of ynamides and propargyl silyl ethers.