New method of preparation of C2F5Li and its reactions with cyclic imines and lactims: Synthesis of α-pentafluoroethyl proline

Addition of pentafluoroethyllithium to cyclic imines leads to pentafluoroethyl substituted pyrrolidines, piperidines and azepanes while reaction of cyclic lactims gives rise to 2-pentafluoroethyl imines. Oxidative cleavage of 2-furyl-2-pentafluoroethyl pyrrolidine has been found to be an effective method for the preparation of a racemic α-pentafluoroethyl proline.

Graphical abstractAddition of pentafluoroethyllithium to cyclic imines leads to pentafluoroethyl substituted pyrrolidines, piperidines and azepanes, while the reaction of imidates gives rise to new 2-pentafluoroethyl five- and six-membered cyclic imines.Figure optionsDownload full-size imageDownload as PowerPoint slide