Substituent effects on the chiral properties of 2,3-dithiadeclins and 2-thiahydrindans

Abstract

Optically active methyl- and phenyl-substituted 2,3-dithiadecalins have been synthesized and their u.v. and c.d. spectra measured. The external perturbation of a methyl group on a disulphide with a dihedral angle ∠CSS/SSC of ca. 60° influences both the 240 and 290 nm bands. The Cotton effect corresponding to the 240 nm transition is especially sensitive to external perturbation. A phenyl group shows such a large influence on the chiral properties that the sign of the Cotton effect at 240 nm expected from the skew conformation of the disulphide group is reversed. A conformationally labile compound has also been investigated, and the effect of substituents on methyl-2-thiahydrindans is described.