Regio- and stereoselective synthesis of the enantiomers of monoterpene-based β-amino acid derivatives
摘要:
The regio- and stereospecific addition of chlorosulfonyl isocyanate to cis-delta-pinene enantiomers has furnished monoterpene-fused beta-lactams. The observed regioselectivity can be explained by ab initio DFT modeling of transition state structures. In contrast with the less reactive alpha-pinane-fused beta-lactam 4, the resulting beta-lactams 5 and 13 containing an amino group connected to a secondary carbon possess similar reactivity to the cycloalkane-fused analogues and can be easily converted to the beta-amino acid and its protected derivatives. The base-catalyzed isomerization of the cis-amino ester afforded the corresponding trans-amino ester in moderate yield. (c) 2007 Published by Elsevier Ltd.
Regio- and stereoselective synthesis of the enantiomers of monoterpene-based β-amino acid derivatives
作者:Zsolt Szakonyi、Tamás A. Martinek、Reijo Sillanpää、Ferenc Fülöp
DOI:10.1016/j.tetasy.2007.09.028
日期:2007.10
The regio- and stereospecific addition of chlorosulfonyl isocyanate to cis-delta-pinene enantiomers has furnished monoterpene-fused beta-lactams. The observed regioselectivity can be explained by ab initio DFT modeling of transition state structures. In contrast with the less reactive alpha-pinane-fused beta-lactam 4, the resulting beta-lactams 5 and 13 containing an amino group connected to a secondary carbon possess similar reactivity to the cycloalkane-fused analogues and can be easily converted to the beta-amino acid and its protected derivatives. The base-catalyzed isomerization of the cis-amino ester afforded the corresponding trans-amino ester in moderate yield. (c) 2007 Published by Elsevier Ltd.
Unusual Temperature-Induced Retention Behavior of Constrained β-Amino Acid Enantiomers on the Zwitterionic Chiral Stationary Phases ZWIX(+) and ZWIX(-)
作者:István Ilisz、Zoltán Pataj、Zsanett Gecse、Zsolt Szakonyi、Ferenc Fülöp、Wolfgang Lindner、Antal Péter
DOI:10.1002/chir.22333
日期:2014.8
The effects of temperature on the chiral recognition of cyclic β‐amino acid enantiomers on zwitterionic [Chiralpak ZWIX(+) and ZWIX(–)] chiral stationaryphases were investigated. Experiments were performed at different mobile phase compositions and under 10°C column temperature increments in the temperature range 10–50°C. Apparent thermodynamic parameters and Tiso values were calculated from plots