Trifluoroacetic acid → 1-Acetyl-4-(2,5-difluorophenyl)-2-methyl-2-phenyl-2,5-dihydro-1H-pyrrole

Participants

Reaction Steps

To a flame-dried flask equipped with stir bar under nitrogen was charged 20-9 (14 mg, 38 μmol) and anhydrous CH2CL2 (1 mL). The resulting solution was treated with trifluoroacetic acid (0.2 mL) and stirred 1 hour at 25° C. Upon completion, the reaction was concentrated, diluted with toluene (5 mL) and again concentrated. The TFA salt was then suspended in CH2CL2 at 25° C., and treated successively with Et3N (50 μL, 380 μmol) and acetic anhydride (25 μL, 20 μmol). After 1 hour, the reaction was complete. The reaction was concentrated and flash column chromatography (SiO2, 0-50% EtOAc/hex gradient) provided 20-10 as a clear oil: 1H NMR (300 MHz, CDCl3) δ 7.36 (m, 5H), 7.03 (m, 3H), 6.22 (m, 1H), 4.82 (m, 2H), 2.15 and 2.05 (s, 3H, rotamers), 1.98 and 1.74 (s, 3H, rotamers); LRMS m/z (M+H) 314.0 found, 314.2 required.

Provenance & Evidence