61266-36-2Relevant articles and documents
Transition-metal-free and facile synthesis of 3-alkynylpyrrole-2,4-dicarboxylates from methylene isocyanides and propiolaldehyde
Chen, Xiaojuan,Fu, Liping,Huo, Xiaoli,Shao, Jiaan,Yu, Liya,Zeng, Linghui,Zhang, Chong,Zhang, Jiankang,Zhu, Huajian
supporting information, p. 16430 - 16433 (2021/10/01)
A transition-metal-free, facile and efficient method for the synthesis of 3-alkynylpyrrole-2,4-dicarboxylates from methylene isocyanides and propiolaldehyde with moderate to good yields has been developed. The direct transformation process and good tolerance of various substituents make it an alternative approach to previous protocols, and potential applications of these investigated compounds are expected with or without post-modifications.
Mimics of Pincer Ligands: An Accessible Phosphine-Free N-(Pyrimidin-2-yl)-1,2-azole-3-carboxamide Framework for Binuclear Pd(II) Complexes and High-Turnover Catalysis in Water
Bumagin, Nikolay A.,Dikusar, Evgenij A.,Ivashkevich, Ludmila S.,Kletskov, Alexey V.,Kolesnik, Iryna A.,Lyakhov, Alexander S.,Petkevich, Sergey K.,Potkin, Vladimir I.
supporting information, (2020/08/12)
We report for the first time cyclic phosphine-free "head to tail"N,N,N pincer-like (pincer complexes mimicking) N-(pyrimidin-2-yl)-1,2-azole-3-carboxamide Pd(II) complexes with deprotonated amide groups as high-turnover catalysts (TON up to 106, TOF up to 1.2 × 107 h-1) for cross-coupling reactions on the background of up to quantitative yields under Green Chemistry conditions. The potency of the described catalyst family representatives was demonstrated in Suzuki-Miyaura, Mizoroki-Heck, and Sonogashira reactions on industrially practical examples. Corresponding ligands could be synthesized based on readily available reagents through simple chemical transformations. Within the complex structures, a highly unusual 1,3,5,7-tetraza-2,6-dipalladocane frame could be observed.
Chemo- And regioselective click reactions through nickel-catalyzed azide-alkyne cycloaddition
Baek, Seung-Yeol,Baik, Mu-Hyun,Choe, Wonyoung,Hong, Sung You,Jeon, Ji Hwan,Jeong, Seo Yeong,Kim, Woo Gyum,Nam, Dongsik
supporting information, p. 3374 - 3381 (2020/05/14)
Metal-catalyzed cycloaddition is an expeditious synthetic route to functionalized heterocyclic frameworks. However, achieving reactivity-controlled metal-catalyzed azide-alkyne cycloadditions from competing internal alkynes has been challenging. Herein, we report a nickel-catalyzed [3 + 2] cycloaddition of unsymmetrical alkynes with organic azides to afford functionalized 1,2,3-triazoles with excellent regio- and chemoselectivity control. Terminal alkynes and cyanoalkynes afford 1,5-disubstituted triazoles and 1,4,5-trisubstituted triazoles bearing a 4-cyano substituent, respectively. Thioalkynes and ynamides exhibit inverse regioselectivity compared with terminal alkynes and cyanoalkynes, affording 1,4,5-trisubstituted triazoles with 5-thiol and 5-amide substituents, respectively. Density functional theory calculations are performed for the elucidation of the reaction mechanism. The computed mechanism suggests that a nickellacyclopropene intermediate is generated by the oxidative addition of the alkyne substrate to the Ni(0)-Xantphos catalyst, and the subsequent C-N coupling of this intermediate with an azide is responsible for the chemo- and regioselectivity.
