1333483-14-9Relevant articles and documents
A Unified Approach for Divergent Synthesis of Heterocycles via TMSOTf-Catalyzed Formal [3+2] Cycloaddition of Electron-Rich Alkynes
Chen, Ping,Cao, Wei,Li, Xiangqian,Shi, Dayong
, p. 4789 - 4794 (2021/09/02)
We present a synthetic protocol for the construction of polysubstituted five-membered heterocycles via TMSOTf-catalyzed formal [3+2] cycloaddition of electron-rich alkynes, which features free from any metal, atom economy and water as the main by-product. Furthermore, alkenyl ether adduct has been verified as the key intermediate. Notably, by utilizing this approach, we can synthesize a broad range of polysubstituted furans, thiophenes and pyrroles, and extend this transformation to deliver fused-polyheterocycles. This reaction can be achieved on a gram scale and the corresponding products are intermediates for producing diverse potentially useful scaffolds. (Figure presented.).
Acid-catalyzed [2 + 2 + 2] cycloaddition of two cyanamides and one ynamide: Highly regioselective synthesis of 2,4,6-triaminopyrimidines
Dubovtsev, Alexey Yu.,Zvereva, Valeria V.,Shcherbakov, Nikolay V.,Dar'In, Dmitry V.,Novikov, Alexander S.,Kukushkin, Vadim Yu.
supporting information, p. 4577 - 4584 (2021/05/31)
Triflic acid (10 mol%) catalyzes the highly regioselective [2 + 2 + 2] cycloaddition between two cyanamides and one ynamide to grant the 2,4,6-triaminopyrimidine core. The developed synthetic method is effective for the preparation of a family of the diversely substituted heterocyclic products (30 examples; yields up to 94%). The synthesis can be easily scaled up and conducted in gram quantities. As demonstrated by the post-functionalizations involving the amino-substituents, the obtained heterocycles represent a useful platform for the construction of miscellaneous pyrimidine-based frameworks. The performed density functional theory calculations verified a particular role of H+, functioning as an electrophilic activator, in the regioselectivity of the cycloaddition.
Catalyst-Free [4+2] Cycloaddition of Ynamides with 2-Halomethyl Phenols to Construct 2-Amino-4 H-Chromenes and α-Halo Enamides Simultaneously
Wen, Hao,Yan, Weibo,Chen, Ping,Li, Yu,Tang, Yu
, p. 12870 - 12881 (2020/11/02)
We report the development of a facile protocol for the [4+2] cycloaddition of ynamides and 2-halomethyl phenols to afford the corresponding 2-amino-4H-chromenes and α-halo enamides under catalyst-free conditions. The reaction proceeds under mild condition