Synthesis of a chiral artificial receptor with catalytic activity in Michael additions and its chiral resolution by a new methodology.
Xanthone derivatives were tested as organocatalysts for the Michael addition of pyrrolidine to an alpha,beta-unsaturated lactam. The receptors combine a double H-bond donor pattern that resembles the oxyanion hole in natural enzymes, with a sulfone or sulfoxide that acts as a proton-transfer group. Since these compounds cannot be obtained enantiomerically pure from natural sources, chiral resolution was necessary to study their enantioselectivity. For the most promising receptor, this was accomplished using a new methodology that exploits its supramolecular interactions with a chiral guest and that is inspired in dynamic combinatorial chemistry. The success in the resolution of the racemic mixture indicates that this new method offers an alternative to kinetic resolution.
Simón
Luis
L
Organic Chemistry Department, University of Salamanca, 37008, Salamanca, Spain. lsimon@usal.es
Muñiz
Francisco M
FM
de Arriba
Angel Fuentes
AF
Alcázar
Victoria
V
Raposo
César
C
Morán
Joaquín R
JR