(4R)-4-FLUORO-L-PROLINE HCL synthesis

Yield: 93%

Reaction Conditions:

with hydrogenchloride in waterReflux;

Steps:

4.3. tert-butyl (2S,4S)-4-fluoropyrrolidine-2-carboxylate (10a)
General procedure: Compound 15a (1.89 g, 7.64 mmol) was dissolved in 10 mL of 2NHCl. The resulting solution was heated under reflux for 2-4 h. After thereaction was complete (as monitored by TLC), the solution was decolorizedwith charcoal while still hot, and filtered through a pad of celite.Water was removed by rotary evaporation and further dried withazeotropic distillation with dry toluene under reduced pressure.Recrystallization (1:1 ethyl acetate/petroleum ether) afforded the hydrochloridesalt of 11a (1.1 g, 85%) as a white solid.

References:

Liu, Ting;Yan, Nan;Zhao, Hui;Wang, Zhen-Xing;Hu, Xiang-Guo [Journal of Fluorine Chemistry,2018,vol. 207,p. 18 - 23]