Unprecedented Aromatic Homolytic Substitutions and Cyclization of AmideIminyl Radicals: Experimental and Theoretical Study
作者:Aurore Beaume、Christine Courillon、Etienne Derat、Max Malacria
DOI:10.1002/chem.200700884
日期:2008.1.28
a tin-free radical cascade cyclization process. Not only do amide-iminyl radicals lead to new tetracyclic heterocycles but these nitrogen-centered radical species also react in aromatic homolytic substitutions. Indeed, the amide-iminyl radical moiety unprecedentedly displaces methyl, methoxy, and fluorine radicals from an aromatic carbon atom. This seminal reaction in the field of radical chemistry
酰胺亚胺基是N-酰基氰酰胺级联自由基环化中的通用有效中间体。它们很容易被烯烃或(杂)芳环捕获并环化为一系列带有吡咯并喹唑啉部分的新杂环化合物。为了说明这些化合物的合成重要性,通过锡-自由基级联环化过程实现了天然抗肿瘤化合物褪黑素A的全合成。不仅酰胺亚胺基会生成新的四环杂环,而且这些以氮为中心的自由基也会在芳族均溶取代反应中发生反应。实际上,酰胺-亚氨基基团部分前所未有地取代了芳族碳原子上的甲基,甲氧基和氟基团。