Department of Biomolecular Science, Faculty of Science, and ‡Research Center for Materials with Integrated Properties, Toho University , Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan.
J Org Chem. 2017 Jun 2;82(11):5663-5668. doi: 10.1021/acs.joc.7b00486. Epub 2017 May 19.
Three-bladed propeller-shaped triple [5]helicene was synthesized using eliminative and oxidative photocyclization reactions, which proceeded in 37 and 63% yields, respectively. Chromatographic purification gave a mixture of diastereomers, and the PPM and PMM isomers were gradually converted to the thermodynamically more stable PPP and MMM isomers at room temperature. The activation parameters for the racemization of the PPP and MMM isomers were determined, and the structure of the triple [5]helicene was determined by X-ray crystallographic analysis.
使用消除和氧化光环化反应合成了三叶桨形三[5]轮烯，产率分别为 37%和 63%。色谱纯化得到了非对映异构体的混合物，并且 PPM 和 PMM 异构体在室温下逐渐转化为热力学上更稳定的 PPP 和 MMM 异构体。确定了 PPP 和 MMM 异构体外消旋化的活化参数，并通过 X 射线晶体学分析确定了三[5]轮烯的结构。
