The asymmetric Michael addition of aromatic heterocyclic aldehydes to arylidenemalonates catalyzed by N-heterocyclic carbenes is described. The ketomalonates are obtained in 84-98% yields and moderate to good enantioselectivities (30-78% ee). The enantiomeric excesses could be improved to excellent levels of up to 99% ee after a single recrystallization.
介绍了在 N-杂环碳烯催化下,芳香杂环醛与亚芳基
丙二酸酯的不对称迈克尔加成反应。
酮丙二酸盐的产率为 84-98%,对映选择性为中等至良好(30-78% ee)。经过一次重结晶,对映体过量可提高到高达 99%ee 的优异
水平。