Enantiomerically Pure Tetrahydropyrimidinones in Asymmetric Synthesis: Preparation of a Protected α-Methylasparagine Derivative and Corresponding Dipeptides
1999; American Chemical Society; Volume: 64; Issue: 21 Linguagem: Inglês
10.1021/jo9909296
ISSN1520-6904
AutoresStephanie A. Hopkins, Todd A. Ritsema, Joseph P. Konopelski,
Tópico(s)Click Chemistry and Applications
ResumoMethyl ester 5a, available in enantiomerically pure form from the amino acid asparagine via a one-pot cyclization/protection sequence, followed by esterification, can be effectively deprotonated with LDA/DMPU/LiCl. Treatment with MeI affords the corresponding alkylated adduct in enantiomerically pure form, from which α-methylaspartic acid is obtained. Variation of the amine protection group allows for the isolation of a protected carboxylic acid/free amine derivative of α-methylasparagine. The utility of H-MeAsn-OMe is demonstrated in the formation of dipeptides.
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