Highly enantioselective phase-transfer catalytic alkylation in the preparation of non-natural alpha-amino acids via solid phase synthesis using aldimine linker.
A new Merrifield-resin-derived glycinimine tert-butyl ester (9) was prepared and applied to the enantioselective synthesis of non-natural alpha-amino acids. High enantioselectivities (86 to >99% ee) were accomplished by employing the aldimine linker under phase-transfer alkylation conditions, using 50% aqueous CsOH in toluene/chloroform (7:3) at 0 degrees C in the presence of N-(9-anthracenylmethyl)-O(9)-allylcinchonidium bromide (10 mol %).
Park
Hyeung-geun
HG
Research Institute of Pharmaceutical Science and College of Pharmacy, Seoul National University, Seoul 151-742, Korea. hgpk@plaza.snu.ac.kr
Kim
Mi-Jeong
MJ
Park
Mi-Kyung
MK
Jung
Hyun-Ju
HJ
Lee
Jihye
J
Choi
Sea-hoon
SH
Lee
Yeon-Ju
YJ
Jeong
Byeong-Seon
BS
Lee
Jeong-Hee
JH
Yoo
Mi-Sook
MS
Ku
Jin-Mo
JM
Jew
Sang-sup
SS
D000478:Alkylation; D000596:Amino Acids / Q000138:chemical synthesis*; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D008968:Molecular Conformation; D013237:Stereoisomerism
D000596:Amino Acids; D003432:Cross-Linking Reagents; D007097:Imines