Efficient Synthesis of 1H-Benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-one Derivatives Using Ag2CO3/TFA-Catalyzed 6-endo-dig Cyclization: Reaction Scope and Mechanistic Study
作者:Abdelkarim El Qami、Badr Jismy、Mohamed Akssira、Johan Jacquemin、Abdellatif Tikad、Mohamed Abarbri
DOI:10.3390/molecules28052403
日期:——
oxacyclization of N-Boc-2-alkynylbenzimidazole substrates. In all experiments, the 6-endo-dig cyclization was exclusively achieved since the possible 5-exo-dig heterocycle was not observed, indicating the high regioselectivity of this process. The scope and limitations of the silver catalyzed 6-endo-dig cyclization of N-Boc-2-alkynylbenzimidazoles as substrates, bearing various substituents, were investigated
1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-one 衍生物的小型文库以优良的产率制备,涉及 Ag2CO3/TFA 催化的 N 分子内氧杂环化-Boc-2-炔基苯并咪唑底物。在所有实验中,由于未观察到可能的 5-exo-dig 杂环,因此完全实现了 6-endo-dig 环化,表明该过程具有高区域选择性。研究了 N-Boc-2-炔基苯并咪唑作为底物、带有各种取代基的银催化 6-内切-环化的范围和局限性。虽然 ZnCl2 显示出对带有芳香族取代基的炔烃的限制,但 Ag2CO3/TFA 证明了其有效性和相容性,无论起始炔烃的性质(脂肪族、芳香族或杂芳族)如何,为结构多样的 1H-苯并[4,5]咪唑并[1,2-c][1,3]oxazin-1-ones 提供实用的区域选择性途径,产率高。此外,一项互补的计算研究解释了 oxacyclization 选择性的合理化,有利于