New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions
作者:Helge Klare、Jörg M Neudörfl、Bernd Goldfuss
DOI:10.3762/bjoc.10.18
日期:——
catalysts based on open-chain P(V)-amides of BINOL and chinchona alkaloids as well as three catalysts based on rigid cis-P(V)-cyclodiphosphazane amides of N (1),N (1)-dimethylcyclohexane-1,2-diamine have been developed. Employed in the asymmetric Michael addition of 2-hydroxynaphthoquinone to beta-nitrostyrene, the open-chain 9-epi-aminochinchona-based phosphorus amides show a high catalytic activity
十种基于 BINOL 和金鸡纳生物碱的开链 P(V)-酰胺的新型氢键催化剂以及三种基于 N (1),N (1)- 刚性顺式-P(V)-环二磷氮烷酰胺的催化剂已开发出二甲基环己烷-1,2-二胺。在 2-羟基萘醌与 β-硝基苯乙烯的不对称迈克尔加成中,基于开链 9-epi-aminochinchona 的磷酰胺表现出高催化活性,几乎定量的产率高达 98%,对映体过量高达 51% . 环二磷氮烷催化剂表现出同样的高活性,并改善了高达 75% 的对映体过量,从而代表了环二磷氮烷在对映选择性有机催化中的首次成功应用。DFT 计算表明,与脲基催化剂相比,环二磷氮烷 P(V)-酰胺具有较高的氢键强度。对顺式环二磷氮烷 14a 的对映测定步骤的实验结果和计算表明,催化剂对硝基苯乙烯底物有很强的双齿 H 键活化。