一种含有手性联萘“铰链”单元的环芳分子的设计、合成及表征

基于联萘衍生物手性构型高度稳定以及联萘结构中2个萘平面的两面角可以在一定范围内张合的特点, 分别以光学活性的(R)和(S)-2,2'-二乙炔基-1,1'-联萘为模板, 设计了一种含有8个“铰链”结构单元的新的环芳分子¾—(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3. 其合成路线涉及间苯基连接桥的链接, 保护基的脱去和控制导入以及分子间偶合等步骤. 用MS, IR, UV-Vis, ¹H和¹³C NMR以及元素分析等技术对中间体和目标化合物进行了结构表征. 测定并比较了2个目标化合物的比旋光度α]_D和圆二色(CD)性质. 在CH₂Cl₂溶液中, 两个异构体(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3的α]_D²⁵值分别为－911.8和＋908.6, 并且它们的CD谱表现出对称的镜像特征．这些实验结果清楚地反映了它们之间的对映异构关系.

Design, Synthesis and Characterization of a New Type of Cyclo-phane Containing Chiral Binaphthyls as Hinges Units

Based on highly stable chiral configuration of binaphthyls and behavior of extension/contraction of the dihedral angle between the two naphthalene rings in binaphthyl, we have designed two cyclophane enantiomers (R,R,R,R,R,R,R,R)-3 and (S,S,S,S,S,S,S,S)-3 containing eight chiral binaphthyl units by utilizing (R) and (S)-2,2'-diethynyl-1,1'-binaphthyl as hinges template, respectively. The synthetic procedure involved the multi steps reactions including the linking of meta-substituted benzene-bridge, removal and control introduction of protecting group, as well as intermolecular cross-coupling, etc. MS, IR, ¹H and ¹³C NMR as well as elemental analysis characterized intermediates and target compound 3. The specific rotations (α]_D) of two isomers in CH₂Cl₂ are －911.8 and ＋908.6, and their circular dichroism (CD) spectra represented exactly mirror images of each other. These results reflected unambiguously enantiomeric relation between two optically pure isomers.