η<sup>3</sup>-Pyranyl and η<sup>3</sup>-Pyridinyl Molybdenum π-Complexes as Chiral Scaffolds for the Enantioselective Construction of Substituted Oxa- and Aza[3.3.1]bicyclics: First Enantio- and Regiocontrolled [5+3] Cycloaddition Reactions
作者:Ramón Gómez Arrayás、Lanny S. Liebeskind
DOI:10.1021/ja035424i
日期:2003.7.1
cycloadditions are reported. 3-Substituted pyranyl and pyridinyl molybdenum pi-complexes participate in enantiocontrolled [5+3] cycloadditions and provide a new and efficient synthetic approach to oxa- and aza[3.3.1]bicyclics of high enantiomeric purity. The reaction proceeds in good to excellent yields and with complete regio- and endo-selectivities; it diverts to a [2+3] cycloaddition pathway when 2-substituted
报道了第一个 Mo 介导的 [5+3] 环加成。3-取代的吡喃基和吡啶基钼 pi 络合物参与对映控制的 [5+3] 环加成,并为高对映体纯度的氧杂和氮杂 [3.3.1] 双环化合物提供了一种新的有效合成方法。该反应以良好的收率和完全的区域选择性和内向选择性进行;当使用 2-取代的杂环 pi 络合物时,它转向 [2+3] 环加成途径。这种方法与各种通用脱金属协议相结合,在合成应用中具有很大的前景。
Vinyl Oxocarbenium Ions in Intermolecular [4 + 3] Cycloaddition Reactions