Optically Switchable Helicenes for Enantiodivergent Steglich Rearrangement and Deracemization through Complementary Supramolecular Interaction

• Main Authors: Tsai, Cheng Che, 蔡政哲
• Other Authors: Chen, Chien Tien
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/x8c535

博士 === 國立清華大學 === 化學系 === 105 === In chapter 1, a pseudo-enantiomeric pair of optically switchable helicenes containing a catalytic 4-N-methylaminopyridine (MAP) bottom unit and a C2-symmetric, (10R,11R)-dimethoxymethyl-dibenzosuberane top template was synthesized. The helicenes underwent complementary photoswitching at 290 nm (P/M’, <1/>99) and 340 nm (P/M’, 91/9) and unidirectional, thermo-rotation at 130 oC (P/M’, 100/0). They were utilized to catalyze enantiodivergent Steglich rearrangement of O- to C-acylated azlactones, with formation of either enantiomers with up to 90% ee (R) and 94% ee (S), respectively. In chapter 2, a photoswitchable, racemic helicene derived from 3,7-gallamide-substituted dibenzosuberene and 8-phenyl-α-azo-tetraline was synthesized. Doped with 25% analogues chiral helecene, the racemic helicene underwent photoswitchings at 270 and 335 nm, leading to exclusive formation of complementary enantiomeric helicenes. The amplification of helical chirality was induced by supramolecular co-assembly with doped chiral analogue as evidenced by SEM analysis of forming gel fibers.