Carbon Dioxide → Tri-n-butyltrifluoromethylsilane

Participants

Reaction Conditions

Reaction Steps

A flask equipped with a dry ice condenser was flame dried under a nitrogen steam, and charged with 5.0 g (20 mmol) of chlorotri-n-butylsilane and 10 mL of dichloromethane. After cooling the resulting solution to -78° C. and charging the condenser with dry ice and acetone. 6.2 mL (66 mmol) of bromotrifluoromethane (Freon 13B1) that had been condensed into a graduated tube was warmed to room temperature and allowed to distill into the flask. The cooling bath was removed and the mixture was allowed to warm to the temperature of the refluxing Freon (-59° C.). To this cold solution was added, dropwise, 8.0 mL (29 mmol) of hexaethylphosphorous triamide. The resulting solution was stirred at reflux for 1 hour. Removal of the condenser and continued stirring for 1 hour resulted in evaporation of excess Freon and warming of the solution to room temperature. Dilution with 30 mL of dichloromethane, water (three 30 mL portions) and 1N HCl (two 30 mL portions) washing, drying (MgSO4), and concentration afforded a residue which was short path distilled to give 3.6 g (64% yield) of tri-n-butyltrifluoromethylsilane: bp 53°-58° C. at 0.5 torr; 1H NMR (CDCl3) 0.60-1.10 (m, 5H), 1.10-1.56 (m, 4H); 19F NMR (CDCl3, relative to CFCl3)δ-61.6 ppm (s); IR (neat) 2956, 2925, 2872, 1214, 1058 cm-1 ; mass spectrum (70eV) m/z (relative intensity) 199 (30,M-CF3), 143 (80), 105 (30), 101 (27), 87 (30), 77 (66), 63 (43), 59 (41 ), 55 (54), 47 (25), 43 (20), 41 (100). Anal. Calcd. for C13H27F3Si: C, 58.16; H, 10.14. Found: C, 58.26; H, 10.09.

Provenance & Evidence