Enantiomerically pure chiral pyridino-crown ethers: synthesis and enantioselectivity toward the enantiomers of alpha-(1-naphthyl)ethylammonium perchlorate

Seven new enantiomerically pure chiral pyridino-crown ethers (S,S)-4-(R,R)- 10 were prepared. Three of them [(S,S)-4, (S,S)-7 and (R,R)-10] contain one , and two of them [(S,S)-5 and (S,S)-8] contain two linker chains with a te rminal double bond. These linker chains were connected to the carbon atom a t position 9 (opposite the pyridine moiety) of the macrocycle. The terminal double bond of the linker makes it possible to attach these ligands to sil ica gel to obtain chiral stationary phases (CSPs). The enantioselectivity o f the new ligands toward the enantiomers of alpha-(1-naphthyl)ethylammonium perchlorate (NEA) was also determined by a titration H-1 NMR method. (C) 1 999 Elsevier Science Ltd. All rights reserved.