Dichloromethane → Benzyl N-(tert-butoxycarbonyl)-4-(2-tert-butyl-1,1-dioxido-3-oxo-2,3-dihydroisothiazol-5-yl)-L-phenylalaninate

Participants

Reaction Conditions

Reaction Steps

A solution of benzyl(2S)-2-[(tert-butoxycarbonyl)amino]-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate (3.33 g, 6.92 mmol), 2-tert-Butyl-5-chloro-1,1-dioxo-1,2-dihydro-1λ6-isothiazol-3-one (1.86 g, 8.31 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), complex with dichloromethane (1:1) (0.68 g, 0.83 mmol), and potassium carbonate (4.78 g, 0.0346 mol) in 1,4-dioxane (25 mL) were added to a flask with a reflux condenser. The reaction atmosphere was evacuated and purged four times with dry nitrogen. The reaction was heated at 80° C. overnight. The reaction mixture was diluted with water and extracted with ethyl acetate. ethyl acetate extracts were washed with saturated brine and dried over anhyd. sodium sulfate, filtered and concentrated to an oil. The crude was eluted with 10%–30% ethyl acetate in hexanes to give the product (1.4 g, 37%). LCMS found for C28H35N2O7S (M+H)+: m/z=543.

Provenance & Evidence