Novel highly fluorescent dendritic chiral amines: Synthesis and optical properties

An efficient approach to dendritic chiral amines through the allylation of optically active imines bearing chiral auxiliaries were developed. The addition of allylic zinc catalyzed by CeC1₃·7H₂O to chiral imines derived from 2-thiophenecarboxaldehyde and α-amino acid esters conveniently and efficiently afforded the corresponding homoallylic amines with excellent diastereoselectivity. Such addition reactions employing diimines or triimines of the polycyclic aromatic derivatives also produced the chrial multiallylic dendritic amines with the similar diastereoselectivity. The investigation of their photophysical properties including UV-vis absorption and fluorescence spectra as well as circular dichroism (CD) indicated that it did not affect the absorption of the precursors to induce the chiral auxiliaries; however, that the whole molecules exhibited the obvious CD behaviors.