The synthesis of γ-benzo[b]furanyl malonates was achieved through the addition of benzo[b]furan to activated cyclopropanes. These Friedel-Crafts reactions were catalyzed by calcium bis(trifluoromethanesulfonimide), Ca(NTf₂)₂ with tetrabutylammonium hexafluorophosphine as a co-catalyst. The additions proceeded with complete regioselectivity and in good to excellent yield. Optimization of the reaction conditions and investigation into the scope of the methodology with regards to substitution on the cyclopropane are reported.

中文翻译：

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钙（II）配合物催化的活化环丙烷的苯并[ b ]呋喃的弗里德-克来福特烷基化

γ-苯并[ b ]呋喃基丙二酸酯的合成是通过将苯并[ b ]呋喃添加到活化的环丙烷中来实现的。用双（三氟甲磺酰亚胺）钙，Ca（NTf ₂）₂和四丁基铵六氟膦作为助催化剂催化这些Friedel-Crafts反应。添加以完全的区域选择性进行并且以良好至优异的产率进行。报道了反应条件的优化和关于在环丙烷上取代的方法范围的研究。