Design and Efficient Synthesis of Amino Acid Derived 2-Substituted Imidazoles by Palladium-Catalyzed Cross-Coupling Reactions
作者:Filip Bureš、Aleš Marek、Jiří Kulhánek
DOI:10.1055/s-0028-1083263
日期:2009.1
Optically active imidazole derivatives featuring an α-amino acid motif substituted at the 2-position can be prepared in moderate to good yields by Negishi as well as Suzuki-Miyaura cross-couplings as the key synthetic steps. The reaction sequence involves N-protection (ethoxymethylation), whereby both generated regioisomers could be separated by column chromatography, and selective 2-lithiation. Subsequent transmetalation to zinc or an iodine quench affords reactants suitable for Pd-catalyzed Negishi and Suzuki-Miyaura reactions with (hetero)aromatics.