The gas phase and solution CD spectra of (1R)-5exo,5exo- and (1R)-5exo- (epoxy-methano)-2,3-dimethylidenebicyclo[2.2.1]heptanes have epposite Cotton effects for their V ← N transitions. An “extra” band is observed at ca. 215 nm for the endo epoxydiene only. ... J. Am. Chem. Soc., 103 (1981), p. 5314 and references cited therein. ... See: C. Mahain, L. Schwager, P.-A. Carrupt & P. Vogel, preceding paper. ... Characteristics of (1R)-9: [α] 23 ...