Amino Acid Derived Heterocycles: Lewis Acid Catalyzed and Radical Cyclizations from Peptide Acetals
作者:Matthew H. Todd、Chudi Ndubaku、Paul A. Bartlett
DOI:10.1021/jo010990m
日期:2002.6.1
of peptide acetals via nucleophilic attack of a phenyl group on an endocyclic acyliminium ion 4 was explored as a route to novel amino acid derived heterocycles and peptidomimetic scaffolds. In the presence of protic acid, bridged structures such as 6 are formed readily from phenylalanine derivatives, but the fused-ring analogues 5 could not be obtained in good yield. In contrast, radical cyclization
肽缩醛的双环化是通过内环酰基酰亚胺离子4上的苯基的亲核攻击而探索的,这是通往新型氨基酸衍生的杂环和拟肽骨架的途径。在质子酸的存在下,由苯丙氨酸衍生物容易形成诸如6的桥连结构,但是不能以高收率获得稠环类似物5。相反,溴苯基二氢吡嗪酮7的自由基环化为5的合成(n = 0、1、2)提供了有效的替代方法。有效合成不同的稠环系统(以抗蠕虫药吡喹酮为代表)证明了该方法的更多用途。