Synthesis of Chiral Bicyclic Bis-lactam Components for the controlled self-assembly of hydrogen-bonded arrays
作者:Marie-JosèPhe Brienne、Jacqueline Gabard、Martine Leclercq、Jean-Marie Lehn、Michel Chevé
DOI:10.1002/hlca.19970800320
日期:1997.5.12
through a sequence involving thiocarbonylation followed by reduction (Scheme 5). Thereafter, the double intramolecular cyclization of the resulting diamino diester 22c proceeded easily to afford 2′b. This intermediate may be transformed via the tetrol 2′g or the diol 2′h into the N-protected derivatives of 2 (X = OR) and of 3 (X = OCOR). Cleavage of the 4-alkuxybenzyl groups was achieved by ceric ammonium
结构的手性biyclic双内酰胺3和4是从关键中间体合成2'B,将N,N'-双(4-甲氧基苄基)衍生物的2(X = MEO)(方案6)。该中间体的合成涉及两个关键步骤:(1)乙醛酸/茴香酰胺(=氧乙酸/ 4-甲氧基苯甲酰胺)加合物11c与四氢呋喃(1,2-二甲氧基苯;10)的双缩合反应允许引入两个甘氨酸单元在四环的4,5位上得到18c(方案3和4); (2)为了避免被证明是不可行的4-甲氧基苯甲酰基保护基的水解,通过涉及硫羰基化的序列将这些基团转化为4-甲氧基苄基,然后还原(方案5)。此后,容易地进行所得二氨基二酯22c的双分子内环化,得到2'b。该中间体可以通过四氢萘2'g或二醇2'h转化为2(X = OR)和3的N保护衍生物(X = OCOR)。通过硝酸铈铵实现4-羟基苄基的切割。但是,当芳香环带有醚的官能团(N-保护的2)时,该正常反应伴随着氧化环的裂解,得到二烯-二酯结构4(方案5和6)。