Cooperative Dienamine/Hydrogen-Bonding Catalysis: Enantioselective Formal [2+2] Cycloaddition of Enals with Nitroalkenes
作者:Garazi Talavera、Efraím Reyes、Jose L. Vicario、Luisa Carrillo
DOI:10.1002/anie.201200269
日期:2012.4.23
Two can play this game: The title reaction is catalyzed by a chiral secondary amine in the presence of an achiral thiourea for the enantio‐ and diastereoselective synthesis of highly functionalized cyclobutanes (see scheme; TMS=trimethylsilyl). Mechanistically, two consecutive Michael reactions proceed through an unprecedented combination of an dienamine/iminium activation mode.
两个可以玩这个游戏:在手性仲胺的存在下,手性仲胺催化标题反应,用于高功能化环丁烷的对映和非对映选择性合成(参见方案; TMS =三甲基甲硅烷基)。从机理上讲,两个连续的迈克尔反应是通过前所未有的二烯胺/亚胺活化方式进行的。