Selective Defluorination Approach to <i>N-</i>Cbz-3,3-difluoro-2-difluoromethylenepyrrolidine and Its Application to 3,3-Difluoroproline Dipeptide Synthesis
作者:Yong Guo、Kana Fujiwara、Hideki Amii、Kenji Uneyama
DOI:10.1021/jo070719q
日期:2007.10.1
Mg-promoted defluorination of N-(p-methoxyphenyl)bis(trifluoromethyl)imine 1 gave perfluoroenamine 2, which was readily transformed to N-Cbz-2-trifluoromethyl-3,3-difluoropyrrolidine 10. Chemoselective defluorination from the trifluoromethyl group of 10 by LHMDS-promoted dehydrofluorination in THF provided 3,3-difluoro-2-difluoromethylenepyrrolidine 11. The product 11 was converted to 3,3-difluoroproline
Mg促进N-(对甲氧基苯基)双(三氟甲基)亚胺1的脱氟,得到全氟烯胺2,该全氟烯胺2易于转化为N -Cbz-2-三氟甲基-3,3-二氟吡咯烷10。在THF中由LHMDS促进的脱氟化氢作用从10的三氟甲基进行化学选择性脱氟化,得到3,3-二氟-2-二氟亚甲基吡咯烷11。用氨基酯处理后,产物11转化为3,3-二氟脯氨酸二肽16。