| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1348878 | Tetrahedron: Asymmetry | 2010 | 7 Pages |
A series of rigid and chiral C2-symmetric 18-crown-6 type macrocycles (S,S)-4, (S,S)-5, (S,S)-6 and (R,R)-2 bearing diamide–ester groups were synthesized. The binding properties of these macrocycles were examined for α-(1-naphthyl)ethylammonium perchlorates salts by an 1H NMR titration method. Taking into account the host employed, important differences were observed in the Ka values of (R)- and (S)-enantiomers of guests for macrocycles (S,S)-4 and (S,S)-6, KS/KR = 3.6, and KS/KR = 0.1 (KR/KS = 10.3) ΔΔG = 3.19 and ΔΔG = −5.77 kJ mol−1, respectively. The results indicated excellent enantioselectivity of macrocyclic (S,S)-6 towards the enantiomers of α-(1-naphthyl)ethylammonium perchlorate salts.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide
N,N′-Bis[(1S)-1-benzyl-2-hydroxyethyl]diglycoldiamideC22H28N2O5[α]D34=-39.2 (c 0.03, MeOH)Source of chirality: l-phenylalanilolAbsolute configuration: (S,S)
N,N′-Bis[(1S)-2-hydroxyethyl-1-isobutyl]diglycoldiamideC16H32N2O5[α]D39.5=-40.3 (c 1, MeOH)Source of chirality: l-leucinolAbsolute configuration: (S,S)
N,N′-Bis[(1S)-2-hydroxyethyl-1-(S)-sec-butyl]diglikoldiamideC16H32N2O5[α]D41=-21.3 (c 1, MeOH)Source of chirality: l-isoleucinolAbsolute configuration: (S,S,S,S)
N,N′-Bis[(1R)-1-ethyl-2-hydroxyethyl]diglycoldiamideC12H24N2O5[α]D39=-22.7 (c 1, MeOH)Source of chirality: (R)-(−)-2-amino-1-butanolAbsolute configuration: (R,R)
(9,17S)-9,17-Dibenzyl-1,4,7,13-tetraoxa-10,16-diaza-cyclooctadecane-2,6,11,15-tetraoneC26H30N2O8[α]D31=-109 (c 0.01, THF)Source of chirality: l-phenylalanilolAbsolute configuration: (S,S)
(9,17S)-9,17-Diisobutyl-1,4,7,13-tetraoxa-10,16-diaza-cyclooctadecane-2,6,11,15-tetraoneC20H34N2O8[α]D31=-32 (c 0.01, THF)Source of chirality: l-leucinolAbsolute configuration: (S,S)
(9,17S)-9,17-(S)-Di-sec-butyl-1,4,7,13-tetraoxa-10,16-diaza-cyclooctadecane-2,6,11,15-tetraoneC20H34N2O8[α]D31=-30 (c 0.01, THF)Source of chirality: l-isoleucinolAbsolute configuration: (S,S,S,S)
(9,17R)-9,17-Diethyl-1,4,7,13-tetraoxa-10,16-diaza-cyclooctadecane-2,6,11,15-tetraoneC16H26N2O8[α]D34=+51 (c 0.01, THF)Source of chirality: (R)-(-)-2-amino-1-butanolAbsolute configuration: (R,R)
