Inter- and intramolecular carbonyl-ene reactions have been developed using 5 mol% Fe(BF 4 ) 2 as catalyst, affording homoallylic alcohols in 36–87% isolated yields. This catalyst, prepared from FeCl 2 and AgBF 4 , is the first Fe II Lewis acid reported for the carbonyl-ene reaction using ethyl trifluoropyruvate. The method was successfully applied to the reaction of various 1,1-disubstituted alkenes with ethyl trifluoropyruvate and to the cyclization of citronellal.

中文翻译：

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Fe(BF4)2-催化三氟丙酮酸的分子间和分子内羰基-烯反应

使用 5 mol% Fe(BF 4 ) 2 作为催化剂开发了分子间和分子内羰基烯反应，以 36-87% 的分离产率提供高烯丙醇。这种由FeCl 2 和AgBF 4 制备的催化剂是第一个报道的使用三氟丙酮酸乙酯进行羰基-烯反应的Fe II路易斯酸。该方法已成功应用于各种1,1-二取代烯烃与三氟丙酮酸乙酯的反应和香茅醛的环化反应。