Optical Rotatory Dispersion and Circular Dichroism of the Osmate Esters of Cyclic Mono-olefins

The osmate esters (as the di-pyridine adducts) of optically active mono-, di- and tricyclic mono-unsaturated terpenes were prepared for measurements of optical rotatory dispersion (ORD) and circular dichroism (CD). All the osmate esters of the cyclic olefins examined exhibited a strong Cotton effect in 470 mμ regions and a weak Cotton effect near 600 mμ regions, which were similar to those of the osmate esters of the open chained olefins reported in our previous paper. The sign of CD maximum in 470 mμ regions was found to be correlated to the chirality of gauche structure of the chelate ring containing an osmium chromophore. Furthermore, their absolute configurations were deduced from the data of circular dichroism of two diastereoisomers of cis-α-pineneglycol.