Mg-promoted facile and selective intramolecular cyclization of aromatic δ-ketoesters
作者:Takeshi Miyazaki、Hirofumi Maekawa、Kazuaki Yonemura、Yoshimasa Yamamoto、Yoshiko Yamanaka、Ikuzo Nishiguchi
DOI:10.1016/j.tet.2010.12.030
日期:2011.2
types of aromatic δ-ketoesters 2, 7, and 9 with Mg-turnings for Grignard reaction at −5 to 0 °C in N,N-dimethylformamide (DMF) containing trimethylsilyl chloride (TMSCl) brought about selective and reductive intramolecular cyclization to give the corresponding α-aryl-α-hydroxycyclopentanones 5, 8, and 10, respectively, in moderate to good yields. Similar reductive intramolecular cyclization of aromatic
各种类型的芳族δ酮酯的治疗2,7和9有Mg-屑用于格氏反应在-5至0℃在Ñ,Ñ二甲基甲酰胺(DMF)含有氯化三甲基硅烷(的TMSCl)带来的选择性的和还原的分子内环化,得到相应的α -芳基- α-hydroxycyclopentanones 5,8,和10,分别在中度至良好的产率。芳香族δ-酮二酸酯14的类似还原性分子内环化反应,然后进行酸性水解和脱羧,很容易得到相应的2-芳基-2-环戊烯-1-酮15。本轻便耦合可以通过从金属Mg的电子转移被发起到的芳族羰基2,7,9,和14,以生成相应的自由基阴离子,随后通过分子内亲核进攻的酯基,得到相应的五元元环化合物5,8,10,和15,分别。