Formal meta-specific intramolecular Friedel–Crafts allylic alkylation of phenols through a spirocyclization–dienone–phenol rearrangement cascade
作者:Mariko Yoshida、Tomoyuki Nozaki、Tetsuhiro Nemoto、Yasumasa Hamada
DOI:10.1016/j.tet.2013.09.042
日期:2013.11
Formal meta-specific intramolecular Friedel–Crafts allylic alkylation of phenols was achieved based on spirocyclization–dienone–phenol rearrangement cascades. Systematic screening of acid catalysts revealed that Sc(OTf)3 was a highly effective catalyst for dienone–phenol rearrangement of spiro[4.5]cyclohexadienones. Using 5 mol % of Sc(OTf)3 as the promoter, various spirocyclic substrates were transformed
正式元特异性分子内弗里德尔-克拉夫茨烯丙基酚的烷基化是基于螺环二烯酮-苯酚重排级联来实现。酸催化剂的系统的筛选表明,钪(OTF)3是为螺[4.5]环己二烯酮的二烯酮-苯酚重排的高度有效的催化剂。使用钪(OTF)的5%(摩尔)3作为启动子,各种螺基底变换为良好至优异的产量相应的酚的衍生物。此外,一锅煮顺序螺环二烯酮-苯酚重排使用钯和钪多催化体系或三苯基甲基阳离子单催化剂体系进行,从而提供相应的元-烯丙基化苯酚衍生物,收率优异。