2,2,2-Trifluoro-N,N-dimethylacetamide

2-(1-(tert-Butyldimethylsilyloxy)-7-phenylheptyl)oxazole (1 equiv) is dissolved in anhydrous THF (8 mL / 0.268 mmol), cooled to -78 °C and tert-BuLi (1.7 M in pentane, 1.3 equiv) is added dropwise under Ar. The reaction mixture is stirred for 1 h at -40 °C, cooled to -78 °C and N,N-dimethyltrifluoroacetamide (2 equiv) is added. The reaction mixture is warmed to room temperature, followed by the addition of water (3 mL) and aqueous 2M HCl (2 mL). The mixture is extracted with EtOAc, washed with saturated aqueous NaCl and dried over Na₂SO₄. Evaporation in vacuo yields the crude product which is purified by flash chromatography (SiO₂, EtOAc/hexanes) yields the trifluoroacetylated compound (58% yield).