Enantioselective synthesis of fluorene derivatives by chiral N-triflyl phosphoramide catalyzed double Friedel–Crafts alkylation reaction
作者:Shou-Guo Wang、Long Han、Mi Zeng、Feng-Lai Sun、Wei Zhang、Shu-Li You
DOI:10.1039/c2ob07168a
日期:——
highly efficient tandem double Friedel–Craftsreaction between indoles and 2-formylbiphenyl derivatives by chiral N-triflyl phosphoramide was realized. Under mild conditions, various 9-(3-indolyl) fluorenederivatives have been obtained in good yield and up to 94% ee. Comparing to their corresponding chiral phosphoric acids, chiral N-triflyl phosphoramides catalyzed reactions led to products with opposite