反应详情

To a solution of tert-butyl 4-hydroxypiperidine-1-carboxylate (25 g, 124 mmol), 2-hydroxy-benzotrifluoride (22 g, 136 mmol) and triphenylphosphine (39 g, 149 mmol) in THF was added diethyl azodicarboxylate (23.5 mL, 149 mmol) dropwise at 0° C. The mixture was then warmed to room temperature and stirred for 14 h. The mixture was concentrated and diluted with Et2O, washed with 1 N NaOH and water and then dried over Na2SO4. The mixture was concentrated and diluted with Et2O/hexanes (35:65). The precipitated phosphine oxide was filtered and the filtrate was concentrated. The residue was purified by column chromatography on silica gel (eluting with 35% Et2O/hexanes) to give tert-butyl 4-[2-(trifluoromethyl)phenoxy]-piperidine-1-carboxylate as a solid.

1. concentrationThe mixture was concentrated
2. additiondiluted with Et2O
3. washwashed with 1 N NaOH and water
4. dry with materialdried over Na2SO4
5. concentrationThe mixture was concentrated
6. additiondiluted with Et2O/hexanes (35:65)
7. filtrationThe precipitated phosphine oxide was filtered
8. concentrationthe filtrate was concentrated
9. customThe residue was purified by column chromatography on silica gel (eluting with 35% Et2O/hexanes)