Sawada Risa, Gon Masayuki, Nakamura Jun, Morisaki Yasuhiro, Chujo Yoshiki
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan.
Chirality. 2018 Oct;30(10):1109-1114. doi: 10.1002/chir.23010. Epub 2018 Aug 20.
A new type of planar chiral (R )- and (S )-4,7,12,15-tetrasubstituted [2.2]paracyclophanes was prepared from racemic 4,7,12,15-tetrabromo[2.2]paracyclophane as the starting substrate. Regioselective lithiation and transformations afforded racemic bis-(para)-pseudo-meta-type [2.2]paracyclophane (4,15-dibromo-7,12-dihydroxy[2.2]paracyclophane). Its optical resolution was performed by the diastereomer method using a chiral camphanoyl group as the chiral auxiliary. The diastereoisomers were readily isolated by simple silica gel column chromatography, and the successive hydrolysis afforded (R )- and (S )-bis-(para)-pseudo-meta-type [2.2]paracyclophanes ((R )- and (S )-4,15-dibromo-7,12-dihydroxy[2.2]paracyclophanes). They can be used as pseudo-meta-substituted chiral building blocks.
一种新型的平面手性（R）-和（S）-4,7,12,15-四取代[2.2]对环芳烷由外消旋4,7,12,15-四溴[2.2]对环芳烷作为起始底物制备而成。区域选择性锂化和转化得到外消旋双（对）-假间位型[2.2]对环芳烷（4,15-二溴-7,12-二羟基[2.2]对环芳烷）。其光学拆分通过非对映体方法进行，使用手性樟脑酰基作为手性助剂。通过简单的硅胶柱色谱法很容易分离出非对映异构体，连续水解得到（R）-和（S）-双（对）-假间位型[2.2]对环芳烷（（R）-和（S）-4,15-二溴-7,12-二羟基[2.2]对环芳烷）。它们可用作假间位取代的手性砌块。
