Chiroptical studies of bicyclic α-diketones

Abstract

On the basis of crystallographic analysis it was established that the α-diketone chromophore in bicyclo[2.2.1]heptane-2,3-diones is planar. C.d. studies of some bicyclic compounds show that the c.d. sign for long-wavelength transition is governed by the octant rule with signs opposite to that known for ketones. The vicinal effect of substituents with the same location in space strongly influences the magnitude of the Cotton effect, but not its sign.