Enantiomeric recognition of amino acid salts by macrocyclic crown ethers derived from enantiomerically pure 1,8,9,16-tetrahydroxytetraphenylenes.
Asymmetric synthesis of (R,R)- and (S,S)-1,8,9,16-tetrahydroxytetraphenylenes was achieved from starting material (2R,3R)-butane-2,3-diol and (2S,3S)-butane-2,3-diol respectively by utilizing a center-to-axis strategy. A series of crown ether compounds 20, 24, and 25 and their corresponding enantiomers derived from chiral tetrahydroxytetraphenylene were synthesized in enantiomerically pure forms. Enantiomeric recognition properties of these hosts toward l- and d-amino acid methyl ester hydrochloride were studied by the UV spectroscopy titration. The tetramer hosts (S,S,S,S,S,S,S,S)-20 and (R,R,R,R,R,R,R,R)-20 exhibited the best enantioselectivities toward L- and D-alanine methyl ester hydrochloride salt with K(L)/K(D) = 4.1 and KD/KL = 3.9, respectively. The new chiral macrocyclic hosts would further enrich the host-guest chemistry.
Department of Chemistry, The Chinese University of Hong Kong Shatin, New Territories, Hong Kong SAR, China.
Chao
C
Cheng
Zongwei
Z
Cai
Xiao-Shui
XS
Peng
Henry N C
HN
Wong
D000596:Amino Acids / Q000737:chemistry*; D043844:Crown Ethers / Q000138:chemical synthesis / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010636:Phenols / Q000138:chemical synthesis / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D013237:Stereoisomerism; D013730:Terphenyl Compounds / Q000138:chemical synthesis / Q000737:chemistry*
D000596:Amino Acids; D043844:Crown Ethers; D047028:Macrocyclic Compounds; D010636:Phenols; D012492:Salts; D013730:Terphenyl Compounds