Asymmetric Synthesis of α-Methyl-α-Amino Acids via Diastereoselective Alkylation of (1S)-(+)-3-Carene Derived Tricyclic Iminolactone

被引:17
|
作者
Lu, Ta-Jung [1 ]
Lin, Cheng-Kun [1 ]
机构
[1] Natl Chung Hsing Univ, Dept Chem, Taichung 40227, Taiwan
来源
JOURNAL OF ORGANIC CHEMISTRY | 2011年 / 76卷 / 06期
关键词
PHASE-TRANSFER CATALYSTS; CHIRAL GLYCINE EQUIVALENT; ENANTIOSELECTIVE SYNTHESIS; STEREOSELECTIVE-SYNTHESIS; C-ALPHA; ALPHA-DISUBSTITUTED GLYCINES; STRUCTURAL VERSATILITY; BIOLOGICAL-PROPERTIES; CINCHONA ALKALOIDS; DIMETHYL-SULFOXIDE; ALANINE TEMPLATE;
D O I
10.1021/jo1022537
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
A novel carene-based alanine-equivalent tricyclic iminolactone 16 has been synthesized via stereoselective dihydroxylation of the double bond, IBX oxidation of the secondary alcohol, esterification of the tertiary alcohol, deprotection of the resulting ester, and subsequent cyclization from commercially available (1S)-(+)-3-carene in 79% overall yield. The iminolactone 16 demonstrated high reactivity toward alkylation with a wide range of electrophiles at room temperature under phase-transfer catalysis conditions. The alkylated products were produced with excellent diastereoselectivities (> 98% de) in good isolated yields (86-94%). High yields (83-91%) of optically pure (S)-alpha-methyl-alpha-substituted-alpha-amino acids were obtained by basic hydrolysis of the dialkylated iminolactones with the recovery of the chiral auxiliary 15 (78-87%).
引用
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页码:1621 / 1633
页数:13
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