Confirmation of the Sector Rule of the Benzenoid Chromophore

Article abstract of DOI:10.1246/bcsj.55.3216

1,2,3,4,4a,9,9a,10-Octahydroanthracene and tetralin derivatives with known absolute configurations were synthesized to estimate the contribution of a methyl substituent at the third sphere to the Cotton effect induced in the benzenoid transitions.The contributions were estimated from the CD spectra obtained based on the conformation of the skeleton deduced by Force Field Theory and the assumption that the contributions are additive.A large contribution was observed for the 1-quasiequatorial-methyl group in the 1L_b benzenoid transition and for the 2-axial-methyl group in the 1L_a benzenoid transition.The sign agreed well with the rule proposed by Snatzke except for the contribution of ring B in the 1L_a benzenoid transition.