tert-Butylsulfinamide, (S)-(-)- → (NE,S)-N-[1-(5-bromo-2-fluorophenyl)-2,2-difluoroethylidene]-2-methylpropane-2-sulfinamide

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(5-bromo-2-fluorophenyl)-2,2-difluoroethanone (intermediate E1.1) (13.2 g, 52.2 mmol) and (S)-(−)-2-methyl-2-propanesulfinamide (6.96 g, 57.4 mmol) in tetrahydrofuran (104 ml) was added at 23° C. titanium(IV) ethoxide (21.4 g, 19.5 ml, 93.9 mmol). The yellow solution was stirred at 70° C. for 3 hours. The cooled reaction mixture was poured into ice water, diluted with ethyl acetate and filtered through a pad of Dicalite. The organic layer was separated and washed with brine and then dried over Na2SO4. Removal of the solvent in vacuum left a yellow oil (18.25 g), which was purified by silica column chromatography 200 g, SiO2 with dichloromethane/heptane 1:1 to give (S,E)-N-(1-(5-bromo-2-fluorophenyl)-2,2-difluoroethylidene)-2-methylpropane-2-sulfinamide (14.49 g, 40.7 mmol, 78.0% yield) as a yellow oil. MS (ISP): m/z=355.9 [M+H]+ and 357.9 [M+2+H]+.

Provenance & Evidence