Novel chiral hydrogen bond donor catalysts based on a 4,5-diaminoxanthene scaffold: application to enantioselective conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes
作者:Tetsuhiro Nemoto、Kazumichi Obuchi、Shinji Tamura、Takashi Fukuyama、Yasumasa Hamada
DOI:10.1016/j.tetlet.2010.12.067
日期:2011.3
Novel chiral hydrogen bond donor catalysts based on a 4,5-diamino-9,9′-dimethylxanthene skeleton were designed and synthesized. Among the phenylurea-amide hybrid molecules prepared from various natural/unnatural chiral amino acids, the phenylalanine-derived catalyst, and the proline-derived catalyst were successfully applied to enantioselective conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes
设计并合成了一种基于4,5-二氨基-9,9'-二甲基x吨骨架的新型手性氢键供体催化剂。在由各种天然/非天然手性氨基酸制备的苯基脲-酰胺杂化分子中,苯丙氨酸衍生的催化剂和脯氨酸衍生的催化剂成功地用于将1,3-二羰基化合物对硝基烯烃的对映选择性共轭加成。使用2-乙酰基环戊酮和2-甲氧基羰基环戊酮作为前手性亲核试剂,向β-芳基硝基链烯的不对称共轭加成反应具有良好的非对映选择性,从而提供了具有全碳四元立体中心的相应产物,收率高达95%ee。