Asymmetric Synthesis of Configurationally Stable Gelander-type p-Terphenyls via Rhodium-catalyzed Intramolecular Double [2+2+2] Cycloaddition

The asymmetric synthesis of configurationally stable oxygen-linked Gethnder-type p-terphenyls has been achieved via the rhodium-catalyzed diastereoselective intramolecular double [2+2+2] cycloaddition of chiral propargylic alcohol-derived hexaynes. Centrochirality of the chiral hexaynes induced the axial chirality to give the Gethnder-type p-terphenyls as single stereoisomers. Photophysical and chiroptical properties of the thus synthesized Gethnder-type p-terphenyls were examined, which revealed that the di-n-butyl- and diphenyl-substituted one shows efficient ultraviolet emission and a relatively large absorption dissymmetry ratio.