trifluoroacetic acid in water 0.5 h; Ambient temperature; Yield given;

1: 1) NaH / 1) CH3CN, r.t., 1 h, 2) THF, r.t., 12 h 2: TFA / H2O / 0.5 h / Ambient temperature View Scheme

1: CCl4, hexamethylphosphorus triamide / 1) -78 to -40 deg C, 2) -40 deg C, 1 h, 3) to r.t., 1 h 2: 1) NaH / 1) CH3CN, r.t., 1 h, 2) THF, r.t., 12 h 3: TFA / H2O / 0.5 h / Ambient temperature View Scheme