Phosphine-Mediated Olefination between Aldehydes and Allenes: An Efficient Synthesis of Trisubstituted 1,3-Dienes with High E-Selectivity

The phosphine-mediated olefination of aldehydes with electron-deficient allenes to afford trisubstituted conjugated dienes in fair to excellent yields with high E-selectivity is described. The reaction represents a new reactivity pattern of allenes with aldehydes and also provides a highly stereoselective synthetic method for preparing conjugated dienes. In the reaction, the phosphine acts as a nucleophilic promoter to generate in situ an active phosphorus ylide which mediates the intermolecular olefination.本描述详述了一种利用膦介导的烯烃化反应，将电子缺乏的共轭双烯与醛反应，以实现三取代共轭二烯的高效合成，产率良好至优异，且具有高E-选择性。该反应展现了共轭双烯与醛之间的一种新颖反应模式，并为一类高度立体选择性的共轭二烯合成方法提供了新的合成途径。在此反应中，膦作为亲核促进剂，现场生成活性磷叶立德，进而介导分子间烯烃化反应。