膦催化α’-亚甲基环戊烯酮的形式[6+2]环加成反应（英文）

Phosphine-Catalyzed Formal [6+2] Cycloadditions of α’-Methylene 2-Cyclopentenones

采用三环己基膦活化α'-亚甲基环戊烯酮底物,通过质子转移使得反应位点迁移,促进远端γ-位与2-烯基-1,3-茚二酮化合物发生分子间Rauhut-Currier类反应,并进一步在β'-位发生分子内Michael加成,从而实现了形式[6+2]环加成反应,以中等至良好收率以及优秀的非对映选择性构建了一系列多取代双环并螺1,3-茚二酮骨架.该反应策略拓展了传统Rauhut-Currier反应的常规反应模式,而该新颖的[6+2]环加成反应途径也有望在有机合成中得到更多的应用.

The formal[6+2] cycloaddition reaction of α'-methylene-2-cyclopentenones and 2-alkylidene-1,3-indanediones was developed under the catalysis of tricyclohexyl phosphine,proceeding in a remote γ-regioselective Rauhut-Currier-type reaction followed by a β'-regioselective intramolecular Michael addition process.An array of fused bicyclic frameworks incorperating a spiro-1,3-indanedione motif were produced in fair to good yields of 48%~76% with excellent diastereoseletivity (generally>19:1 dr).This protocol expands the reaction mode of traditional Rauhut-Currier reaction,which might find further application in organic synthesis.