Nakamura K, Okubo H, Yamaguchi M
Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan.
Org Lett. 2001 Apr 19;3(8):1097-9. doi: 10.1021/ol015550w.
[structure: see text]. All stereoisomers of a cyclic alkyne containing three helicene units, 1,12-dimethylbenzo[c]phenanthrene, are synthesized using a building block. Isomeric [3 + 3]cycloalkynes aggregate in organic solvents. Vapor pressure osmometry reveals dimer formation of (M,M,M)-[3 + 3]cycloalkynes in chloroform and benzene at concentrations above 2 mM. No higher aggregation is observed. The chirality of helicenes plays an important role in self-aggregation, and diastereomeric (M,P,M)-[3 + 3]cycloalkyne forms a dimer only above 15 mM. Aggregation of racemic (M,M,M)-[3 + 3]cycloalkyne or (M,P,M)-[3 + 3]cycloalkyne is much weaker than that of a single enantiomer.
[结构：见文本]。使用一种构建模块合成了含有三个螺旋烯单元的环状炔烃1,12 - 二甲基苯并[c]菲的所有立体异构体。异构的[3 + 3]环炔烃在有机溶剂中聚集。蒸气压渗透法表明，在氯仿和苯中，当浓度高于2 mM时，(M,M,M)-[3 + 3]环炔烃会形成二聚体。未观察到更高程度的聚集。螺旋烯的手性在自聚集过程中起着重要作用，非对映体(M,P,M)-[3 + 3]环炔烃仅在浓度高于15 mM时形成二聚体。外消旋的(M,M,M)-[3 + 3]环炔烃或(M,P,M)-[3 + 3]环炔烃的聚集比单一对映体的聚集弱得多。
