Enantioselective Aza-Diels−Alder Reaction of Aldimines with “Danishefsky-Type Diene” Catalyzed by Chiral Scandium(III)-<i>N</i>,<i>N</i><i>‘</i>-Dioxide Complexes
作者:Deju Shang、Junguo Xin、Yanling Liu、Xin Zhou、Xiaohua Liu、Xiaoming Feng
DOI:10.1021/jo7021263
日期:2008.1.1
A new kind of complex prepared from scandium(III) triflate and l-proline-derived N,N‘-dioxides has been developed to catalyze the enantioselective aza-Diels−Alder reaction between 1,3-butadiene (diene 1) and aldimines 2, affording the corresponding 2,5-disubstituted dihydropyridinones in moderate to high yields (up to 92%) with good enantioselectivities (up to 90% ee) at room temperature. A variety
已经开发了一种由三氟甲磺酸((III)和l-脯氨酸衍生的N,N'-二氧化物制备的新型配合物,以催化1,3-丁二烯(二烯1)和醛亚胺2之间的对映选择性氮杂-Diels-Alder反应。 ,在室温下以中等至高产率(高达92%)提供相应的2,5-二取代二氢吡啶并具有良好的对映选择性(高达90%ee)。发现各种醛亚胺是合适的底物,包括芳族,杂芳族,共轭和脂族亚胺。通过单次重结晶获得了某些产品的对映纯样品(最高99%ee)。通过X射线衍射和CD分析确定产物的绝对构型。在研究1H NMR光谱和正非线性效应的基础上,对催化剂的结构进行了仔细的讨论。