Methanol → (2R)-alpha,alpha-Bis[3,5-bis(trifluoromethyl)phenyl]-2-pyrrolidinemethanol

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of crude (7aR)-1,1-bis(3,5-bis(trifluoromethyl)phenyl)tetrahydropyrrolo[1,2-c]oxazol-3(1H)-one ((R)-32, 11.03 g, 20.0 mmol) in methanol (MeOH, 80 mL, 1975 mmol) was added solid potassium hydroxide (KOH, 3.366 g, 60.0 mmol, 3.0 equiv) at room temperature. The resulting dark reaction mixture was heated to 65° C. and stirred at 65° C. for 22 h. When LCMS showed the reaction was deemed complete, the reaction mixture was cooled to room temperature before the solvent was evaporated under reduced pressure. The residue was then treated with water (100 mL) and extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine, dried over magnesium sulfate (MgSO4), filtered, and concentrated under reduced pressure. The residue was then purified by Combiflash (SiO2) with 0-30% EtOAc/hexane gradient elution to afford (2R)-bis(3,5-bis(trifluoromethyl)phenyl)(pyrrolidin-2-yl)methanol ((R)-33, 8.30 g, 10.51 g theoretical, 79% yield for 2 steps) as a yellow viscous paste. For (R)-33: 1H NMR (CD3OD, 400 MHz) δ ppm 8.24 (s, 2H), 8.16 (s, 2H), 7.85 (s, 2H), 4.49 (t, 1H, J=7.7 Hz), 2.92 (m, 2H), 1.74 (m, 2H), 1.67 (m, 1H), 1.55 (m, 1H); C21H15F12NO (MW, 525.33), LCMS (EI) m/e 526.0 (M++H).

Provenance & Evidence