Calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids for enantioselective synthesis of α-amino acids
Tetrahedron Asymmetry, cilt.19, sa.5, ss.618-623, 2008 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 19 Sayı: 5
- Basım Tarihi: 2008
- Doi Numarası: 10.1016/j.tetasy.2008.02.006
- Dergi Adı: Tetrahedron Asymmetry
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.618-623
- Uşak Üniversitesi Adresli: Evet
Özet
The synthesis of the first calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids has been achieved in two steps from p-tert-butylcalix[4]arene. The catalytic efficiency of the chiral calix[4]arenes 3a-c was evaluated by carrying out the phase-transfer alkylation of N-(diphenylmethylene)glycine ethyl ester with benzyl bromide. Various factors that affect the chemical yield and enantioselectivity were also examined. Benzylation of glycine imine 4 using calix[4]arene-based dimeric catalyst 3a as a chiral phase-transfer catalyst in toluene/CHCl3 mixture (7:3 v/v) at 0 °C gave the best enantioselectivities and yields in the presence of aqueous NaOH. © 2008 Elsevier Ltd. All rights reserved.