Nucleophilic 5-endo-trig cyclization of 2-(trifluoromethyl)allylic metal enolates and enamides: Synthesis of tetrahydrofurans and pyrrolidines bearing exo-difluoromethylene units |
| |
| Authors: | Takeshi Fujita Masahiro Hattori Masaaki Matsuda Ryutaro Morioka Tanner C Jankins Masahiro Ikeda Junji Ichikawa |
| |
| Institution: | Division of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan |
| |
| Abstract: | Ketones and imines bearing a 2-(trifluoromethyl)allylic moiety successfully underwent nucleophilic 5-endo-trig cyclization via their metal enolates and enamides. O- or N-Cyclization proceeded exclusively in each case to afford the corresponding five-membered heterocycles with both exo-difluoromethylene and exo-alkylidene units. On treatment with potassium hexamethyldisilazide (KHMDS) or lithium diisopropylamide (LDA), 2-(trifluoromethyl)allylic ketones or imines provided the corresponding tetrahydrofurans or pyrrolidines bearing a Z-alkylidene group with perfect or substantial stereoselectivity, respectively. |
| |
| Keywords: | Cyclization Fluorine Heterocycle Tetrahydrofuran Pyrrolidine C–F bond activation |
| 本文献已被 ScienceDirect 等数据库收录！ |
