Díaz-Sánchez BR, Iglesias-Arteaga MA, Melgar-Fernández R, Juaristi E. Synthesis of 2-Substituted-5-halo-2,3-dihydro-4(H)-pyrimidin-4-ones and Their Derivatization Utilizing the Sonogashira Coupling Reaction in the Enantioselective Synthesis of α-Substituted β-Amino Acids.
J Org Chem 2007;
72:4822-5. [PMID:
17523668 DOI:
10.1021/jo0705115]
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Abstract
A convenient, one-pot procedure for the synthesis of 1-benzoyl-2(S)-substituted-5-iodo-2,3-dihydro-4(H)-pyrimidin-4-ones by tandem decarboxylation/beta-iodination of the corresponding 6-carboxy-perhydropyrimidin-4-ones was developed. In addition, several 1-benzoyl-2(S)-substituted-5-bromo-2,3-dihydro-4(H)-pyrimidin-4-ones were readily prepared by bromination of 1-benzoyl-2(S)-substituted-2,3-dihydro-4(H)-pyrimidin-4-ones. Subsequently, Sonogashira coupling of the halogenated heterocyclic enones with various terminal alkynes produced 1-benzoyl-2(S)-isopropyl-5-alkynyl-2,3-dihydro-4(H)-pyrimidin-4-ones in good yields. Hydrogenation of the unsaturated C-C moieties in the Sonogashira products followed by acid hydrolysis afforded highly enantioenriched alpha-substituted beta-amino acids.
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