Calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids for enantioselective synthesis of α-amino acids

BOZKURT, SELAHATTİN; Durmaz, Mustafa; Yilmaz, Mustafa; Sirit, Abdulkadir

doi:10.1016/j.tetasy.2008.02.006

Calixarene-based chiral phase-transfer catalysts derived from cinchona alkaloids for enantioselective synthesis of α-amino acids

BOZKURT S., Durmaz M., Yilmaz M., Sirit A.

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.