Chemistry of unique chiral olefins. 1. Synthesis, enantioresolution, circular dichroism, and theoretical determination of the absolute stereochemistry of trans- and cis-1,1',2,2',3,3',4,4'-Octahydro-4,4'- biphenanthrylidenes

Article abstract of DOI:10.1021/ja970667u

Unique chiral olefins, (E)-1,1',2,2',3,3',4,4'-octahydro-4,4'-biphenanthrylidene (1) and its (Z)-isomer 2, were synthesized. When these compounds are directly enantioresolved by using the HPLC Okamoto column with a chiral stationary phase, optically pure enantiomers were obtained. The CD spectra of these chiral olefins exhibit very intense Cotton effects in the ¹B(b) transition region reflecting their strongly twisted π-electron systems. The CD and UV spectra of chiral olefins (M,M)-E-1 and (M,M)-(Z)-2 were theoretically calculated by the π-electron self-consistent field/configuration interaction/dipole velocity molecular orbital method. From the calculation results, the absolute stereostructures of these chiral olefins were theoretically determined to be [CD(+)239.0]-(M,M)-(E)-1 and [CD(+)238.1]-(M,M)-(Z)-2, respectively.