The enantioselective synthesis of polycyclic arom. hydrocarbon (PAH)-based planar chiral cyclophanes was achieved for the first time by the rhodium-catalyzed intramol. regio- and enantioselective [2+2+2] cycloaddn. of tethered diyne-benzofulvenes followed by stepwise oxidative transformations. The thus synthesized planar chiral bent cyclophanes, that possess bent p-terphenyl- and 9-fluorenone-cores, were converted to 9-fluorenol-based ones with excellent ee values of >99% by diastereoselective 1,2-redn. These 9-fluorenol-based cyclophanes exhibited high fluorescence quantum yields, which were significantly higher than that of an acyclic ref. mol. (78-82% vs. 48%). The bending effect on the chiroptical property was also examd., which revealed that the anisotropy factors (gabs values) for electronic CD (ECD) of these 9-fluorenol-based planar chiral bent cyclophanes increase as the tether length becomes shorter. [on SciFinder(R)]
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