An unusual electronic effect of an aromatic-F in phase-transfer catalysts derived from Cinchona-alkaloid

被引:145
作者
Jew, SS [1 ]
Yoo, MS
Jeong, BS
Park, IY
Park, HG
机构
[1] Seoul Natl Univ, Coll Pharm, Seoul 151742, South Korea
[2] Chungbuk Natl Univ, Coll Pharm, Cheongju 361763, South Korea
关键词
D O I
10.1021/ol0267679
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
[GRAPHICS] 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. 0(9)-Allyi-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 94similar to>99% ee.
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页码:4245 / 4248
页数:4
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