3,5-Dimethylisoxazole → (R)-N-(bis(3-(trifluoromethoxy)phenyl)-methylene)-2-methylpropane-2-sulfinamide

Participants

Reaction Conditions

Reaction Steps

(R)—N-(bis(3-(trifluoromethoxy)phenyl)methylene)-2-methylpropane-2-sulfinamide was prepared as described for Procedure 11. Under an Argon atmosphere, 3,5-dimethylisoxazole (0.20 mL) was stirred in anhydrous THF in an oven-dried round bottomed flask at −78° C. nBuLi (2.5 M in hexanes, 0.84 mL, 2.1 mmol) was added dropwise. The resulting yellowish solution was stirred at −78° C. for 2 h. N-(bis(3-(trifluoromethoxy)phenyl)methylene)-2-methylpropane-2-sulfinamide (0.81 g, 1.8 mmol) in THF (2 mL) was added dropwise to the above stirred solution. The reaction mixture was stirred at −78° C. for 5 h, then slowly warmed up to room temperature overnight. Saturated NH4Cl was added, followed by the addition of EtOAc. The organic layer was washed with H2O and brine, dried over Na2SO4, filtered, and concentrated to dryness. The residue was purified by flash chromatography (silica gel, EtOAc/Hexanes=0 to 100%, came out at 100% EtOAc) to give 2-methyl-N-(2-(3-methylisoxazol-5-yl)-1,1-bis(3-(trifluoromethoxy)phenyl)ethyl)propane-2-sulfinamide as light tan viscous oil (0.14 g, yield: 13.5% with 0.55 g recovery of the starting material). LC-MS (ESI) 551.38 (M+H), retention time=3.98 min (10-90% MeOH in H2O with 0.1% TFA in a 4-min run); 1H NMR (400 MHz, CDCl3) δ ppm 7.49-7.40 (m, 2H), 7.37-7.28 (m, 1H), 7.19 (d, J=6.57 Hz, 1H), 7.05-7.14 (m, 4H), 5.70 (s, 1H), 4.61 (s, 1H), 4.14 (d, J=14.40 Hz, 1H), 3.88 (d, J=14.40 Hz, 1H), 2.26 (s, 2H), 2.13 (s, 3H), 1.26 (s, 9H).

Provenance & Evidence