The synthesis of a GSK 2nd generation inhibitor of the hepatitis C virus, by enantioselective 1,3-dipolar cycloaddition between a leucine derived iminoester and tert-butyl acrylate, was studied. The comparison between silver(I) and gold(I) catalysts in this reaction was established by working with chiral phosphoramidites or with chiral BINAP. The best reaction conditions were used for the total synthesis of the hepatitis C virus inhibitor by a four step procedure affording this product in 99% ee and in 63% overall yield. The origin of the enantioselectivity of the chiral gold(I) catalyst was justified according to DFT calculations, the stabilizing coulombic interaction between the nitrogen atom of the thiazole moiety and one of the gold atoms being crucial.
研究了通过手性选择性1,3-偶极环加成反应合成丙型肝炎病毒GSK第二代抑制剂,该反应是由亮氨酸衍生的亚氨酯和叔丁基丙烯酸进行反应。通过使用手性磷酰胺或手性BINAP,建立了银(I)催化剂和金(I)催化剂在该反应中的比较。最佳反应条件用于通过四步反应合成丙型肝炎病毒抑制剂,该产物的ee值为99%,总收率为63%。手性金(I)催化剂的手性选择性来源是通过DFT计算进行证明的,噻唑基团的氮原子与其中一个金原子之间的稳定库仑相互作用至关重要。