Enantioselective Cycloadditions of 2‐Alkenoylpyridine‐
<i>N</i>
‐oxides Catalysed by a Bis(oxazoline)/Cu
<sup>II</sup>
Complex: Structure of the Reactive Intermediate
作者:Alessandro Livieri、Massimo Boiocchi、Giovanni Desimoni、Giuseppe Faita
DOI:10.1002/chem.201002017
日期:2011.1.10
Diels–Alder and 1,3‐dipolar cycloadditions involving (E)‐3‐aryl‐1‐(pyridin‐2‐yl‐N‐oxide)prop‐2‐en‐1‐ones as the 2π components are efficiently catalysed by bis(oxazoline)–CuII complexes. The cycloadducts are obtained in quantitative yields with up to 98 % ee; absolute configurations were determined by X‐ray analysis. The structure of the reactive complex, determined by X‐ray analysis, is fully consistent
bis有效地催化了涉及(E)-3-芳基-1-(吡啶-2-基-N-氧化氮)丙-2-烯-1-酮的Diels-Alder和1,3-偶极环加成反应。(恶唑啉)–Cu II配合物。环加合物的定量收率高达98% ee ; 绝对构型是通过X射线分析确定的。通过X射线分析确定的反应性络合物的结构与催化过程的立体化学结果完全一致(二烯或硝酮接近配位的吡啶-N-氧化物衍生物受阻面较小)。