Derivatization, complexation, and absolute configurational assignment of chiral primary amines: application of exciton-coupled circular dichroism.
We report here a sensitive method for the determination of the absolute configurations of primary amines using exciton-coupled circular dichroism (ECCD). The method works on a microgram scale by derivatization of chiral amines with quinoline chromophores. Complexation of the chiral ligands with metal ion fixes the geometry of the chromophores, resulting in a twist that is governed by the asymmetric carbon configuration and steric environment of the amine. The absolute configurations of the primary amines can be interpreted from the couplets of the ECCD spectra of the derivatized complexes. Crystal structures, 2D NMR studies, and semiempirical calculations provide structural evidence for our model.
Zhang
Jing
J
Department of Chemistry, New York University, New York, NY 10003, USA.
Holmes
Andrea E
AE
Sharma
Akanksha
A
Brooks
Neil R
NR
Rarig
Randy S
RS
Zubieta
Jon
J
Canary
James W
JW