253426-82-3Relevant articles and documents
Cu(I)Br mediated coupling of alkynes with N-acylimine and N-acyliminium ions in water
Zhang, Jianheng,Wei, Chunmei,Li, Chao-Jun
, p. 5731 - 5733 (2002)
A coupling of alkynes with N-acylimines and N-acyliminium ions mediated by Cu(I) was developed in water to generate propargyl amide derivatives.
Switchable [3+2] and [4+2] Heteroannulation of Primary Propargylamines with Isonitriles to Imidazoles and 1,6-Dihydropyrimidines: Catalyst Loading Enabled Reaction Divergence
Tong, Shuo,Wang, Qian,Wang, Mei-Xiang,Zhu, Jieping
supporting information, p. 8332 - 8338 (2016/06/13)
Isonitrile 1 due to its carbene-like reactivity serves generally as a one-carbon synthon in a diverse set of organic transformations. We report in this article that the isocyano group can also act as a polarized triple bond to undergo, as a two-atom synthon, heteroannulation with primary propargylamines 15. In addition, we serendipitously discovered that the reaction pathways can be modulated by simply changing the catalyst loading. In the presence of 0.1?equiv of Yb(OTf)3or TfOH, the reaction between 1 and 15 afforded exclusively imidazoles 16 by a formal [3+2] cycloaddition. At a higher catalyst loading (Yb(OTf)3(0.4?equiv) or TfOH (0.5?equiv)) under otherwise identical conditions, the same reaction furnished 1,6-dihydropyrimidines 17 in good to excellent yields by way of a formal [4+2] cycloaddition process. Mechanistic investigations indicated that both annulations went through an amidine intermediate resulting from the insertion of the isocyano group to the NH bond of the primary amine. Subsequent catalyst-loading-dependent 5-exo-dig or 6-endo-dig cyclization provided selectively the two heterocycles, respectively.
