Tetramethylammonium fluoride → 6-[2-(2-Chloro-4-methoxy-phenyl)-1-hydroxy-1-trifluoromethyl-propyl]-4-methyl-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Conditions

Reaction Steps

To a solution of (RS)-6-[2-(2-chloro-4-methoxy-phenyl)-propionyl]-4-methyl-4H-benzo[1,4]oxazin-3-one (5.56 g, 15.45 mmol) in tetrahydrofuran (280 ml) was added a solution of (trifluoromethyl)trimethylsilane (3.36 g, 23.2 mmol) in tetrahydrofuran (55 ml) dropwise (15 min) at 0° C. Tetramethylammonium fluoride (0.148 g, 1.55 mmol) was added and the mixture was stirred at 0° C. for 30 min. A 1 M solution of tetrabutylammonium fluoride in tetrahydrofuran (13.9 ml) was added dropwise and the mixture was stirred for 45 min at r.t. The reaction mixture was poured on ice-water and extracted twice with AcOEt. The organic phases were washed with water and brine, dried (MgSO4), filtered and concentrated. The product was purified by column chromatography (SiO2, heptane/EtOAc 4:1) to give the title compound (4.9 g) as a white semisolid. MS (m/e)=430.2 [M+H+].

Provenance & Evidence