Acetic acid, 2-[bis(2,2,2-trifluoroethoxy)phosphinyl]-, 1,1-dimethylethyl ester

Synthesis

To a stirred solution of 18-crown-6 (7.18 g, 27.16 mmol), THF (30 mL), bis (2,2,2-trifluoroethyl) phosphite (1) (0.95 mL, 5.97 mmol), KHMDS (13.0 mL, 6.50 mmol, 0.5 M in toluene) was added by syringe in a dropwise manner at -78 oC. After 15 min, tert-butyl bromoacetate (0.80 mL, 5.41 mmol) was added to the round bottom flask and the reaction mixture warmed to room temperature over 4 hr. After workup procedure as outlined in the general method, the crude product was then purified by flash column chromatography (6:1-3:1 hexanes:EtOAc, Rf = 0.19 in 3:1 hexanes:EtOAc) yielding Tert-butyl 2-(bis(2,2,2-trifluoroethyl) phosphoryl) acetate (1.345 g, 3.73 mmol, 69.0%) as a yellow syrup.