Asymmetric alkylation catalyzed by chiral alkali metal alkoxides of TADDOL. Synthesis of α-methyl amino acids
作者:Yu. N. Belokon、K. A. Kochetkov、T. D. Churkina、N. S. Ikonnikov、A. A. Chesnokov、O. V. Larionov、H. V. Kagan
DOI:10.1007/bf02494637
日期:1999.5
enantioselective alkylation of Schiff's bases derived from alanine with reactive alkyl halides. Acid hydrolysis of the reaction products affords (R)-α-methylphenyl-alanine, (R)-α-allylalanine, and (R)-α-methylnaphthylalanine in 61–93% yields and withee 69–94%. When (S,S)-TADDOL is used, the (S)-amino acid is formed. A mechanism explaning the observed features of the reaction is proposed.
结果表明,由 (4R,5R)-2,2-二甲基-1,3-二氧戊环-4,5-双(二苯基甲醇) ((R,R)-TADDOL) 及其一些衍生物形成的醇钠可以用作手性催化剂,用于从丙氨酸衍生的席夫碱与反应性烷基卤化物的对映选择性烷基化。反应产物的酸水解得到 (R)-α-甲基苯基-丙氨酸、(R)-α-烯丙基丙氨酸和 (R)-α-甲基萘丙氨酸,产率为 61-93%,产率为 69-94%。当使用 (S,S)-TADDOL 时,会形成 (S)-氨基酸。提出了解释观察到的反应特征的机制。