Optically active amines—X Optical rotatory dispersion and circular dichroism of the N-salicylidene derivatives of α- and β-phenylalkylamines—the absolute configurations of some phenylnorbornanes

Abstract

ORD and CD measurements are reported for the N-salicylidene derivatives of a number of α and β-phenylalkylamines. The strong positive Cotton effects near 255 and 315 nm shown by the derivatives of(S)-1-indanamine and (1S,2S)-2,3-diphenyl-1-methylpropylamine are in accord with a planar sector rule for the prediction of the sign of the Cotton effects associated with a particular enantiomer of the N-salicylidene derivative of an α-or β-phenylalkylamine. Application of this sector rule to the interpretation of ORD and CD of the N-salicylidene derivatives of (+) exo-3-phenyl-endo-2-norbornanamine hydrochloride and (—)-endo-3-phenyl-endo-2-norbornanamine hydrochloride fixes their absolute configurations as (2S) and (2R), respectively. A tentative reassignment of the (S) configuration is made to (+)-1,2,2-triphenylethylaminehydrochloride on