PREPARATION OF (-)-(M)-PARACYCLOPHANO-HEXAHELICENE FROM (-)-(M)-1,4-DIMETHYLHEXAHELICENE AND ABSOLUTE CONFIGURATION OF 4-SUBSTITUTED PARACYCLOPHANES

Article abstract of DOI:10.1246/cl.1980.1553

Photo-cyclization of a cis-trans mixture of the 1,2-diarylethylene precursor 1 gave 1,4-dimethylhexahelicene (2) whose levorotatory enantiomer with (M)-helicity was converted into (-)-(M)-<2.2>paracyclophano-hexahelicene (7), mp 236-237 degC, <α>(abs)