Jew Sang-Sup, Yoo Mi-Sook, Jeong Byeong-Seon, Park Il Yeong, Park Hyeung-Geun
College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
Org Lett. 2002 Nov 28;4(24):4245-8. doi: 10.1021/ol0267679.
[structure: see text] Various N-benzylcinchonidinium salts were prepared to study electronic factors in the catalytic enantioselective phase-transfer alkylation of glycine anion equivalent. An ortho-fluoro substituent on the benzyl group in the quaternary ammonium salt dramatically increased the enantioselectivity in the alkylation. O(9)-Allyl-N-2',3',4'-trifluorobenzylhydrocinchonidinium bromide (27), which gave the highest enantioselectivity of the catalysts studied, was used to prepare 12 alpha-alkylated amino acid derivatives in 94 approximately >99% ee.
[结构：见正文] 制备了各种N-苄基辛可尼定盐，以研究甘氨酸阴离子类似物催化对映选择性相转移烷基化反应中的电子因素。季铵盐苄基上的邻氟取代基显著提高了烷基化反应中的对映选择性。O(9)-烯丙基-N-2',3',4'-三氟苄基氢化辛可尼定溴化物（27）在所研究的催化剂中对映选择性最高，用于制备12种α-烷基化氨基酸衍生物，对映体过量率为94%至>99%。
