A simple circular dichroism method for the determination of the absolute configuration of allylic amines

Absolute configurations of C(alpha)-chiral primary allylic amines can be determined from the CD spectra of their N-phthaloyl derivatives. This method is based on the exciton coupling of the allowed -pi-pi* transitions in the phthalimide and olefin chromophores: positive helicity of the N-C-alpha-C=C bond system results in a positive Cotton effect at ca. 220 nm, a negative Cotton effect is obtained for the negative helicity N-C-alpha-C=C bond chain. (C) 2000 Elsevier Science Ltd. All rights reserved.