Tributylstannane → Triphenylphosphine Oxide

Participants

Reaction Conditions

Reaction Steps

The F(CF2)8 (CH2)6Br was prepared as follows: In a 100 ml three-necked flask equipped with a condenser, bubbler, nitrogen inlet and magnetic stirrer, 30 mmol (16.38 g) of perfluorooctyl iodide and 45 mmol omega-hexene-1-ol (99%) were placed in an oil bath and heated to 80° C. Then 82 mg (0.5 mmol) azoisobutyronitrile (AIBN) was added in small portions over 45 minutes, and then reaction was carried out with stirring for 5 hours. The raw wax-like semifluorinated alkane iodide, in a small flask, was placed under vacuum to evacuate the excess omega-alkene-1-ol and low boiling substances. Direct dehalogenation was attained by adding 10 ml toluene, 0.493 g (3 mmol) AIBN and 17.44 g of tri-n-butyl tin hydride at 80° C. for 18 hours. Then the solution was poured into 200 ml methanol to decompose the tributyl tin. Rotoevaporation of the methanol and recrystallization of the products from toluene at -15° C. was then carried out. Further purification was carried out by sublimation under 0.2 mm Hg at a temperature just below melting point. The product was F(CF2)8 (CH2)6OH. Analysis on the product gave the following result: 1H NMR (CDC13, δ in ppm), 1.35 (t, 1H, CH2OH), 1.40 (4H, (CH2)2CH2CH2OH), 1.60 1.57 (4H, CF2CH2CH2, and CH2CH2OH), 2.07 (2H, CF2CH2), 3.64(2H,CH2OH). The F(CF2)8 (CH2)6OH was converted to F(CF2)8 (CH2)6Br as follows: In a 100 ml round-bottom flask 4.0 g (10 mmol) F(CF2)8 (CH2)6OH and 4.97 g (0.015 mol) carbon tetrabromide was dissolved in tetrahydrofuran/CH2Cl2 (10 ml/20 ml) solution and cooled down to -5° C. using a brine bath. Then 3.93 g (15 mmol) triphenylphosphine was added in small portions over 15 minutes. The reactant was maintained at -5° C. for one hour and then at room temperature for 6 hours. As reaction proceeded, triphenylphosphine oxide was produced and the solvent became slightly pink due to formation of free bromine. The solvent was rotoevaporated and the products were extracted in 10 ml diethyl ether four times. The crude semifluorinated 1-bromoalkane was purified by reduced pressure distillation. Further purifying was then carried out by passing the partly purified product through a short silica column (12 cm) to absorb the triphenylphosphine oxide followed by subliming in a 0.2 mm Hg vacuum at a temperature just below the melting point. Analysis of the F(CF2)8 (CH2)6Br product gave 1H NMR (CDC13, δ in ppm), 3.41 (t, 2H, CH2Br) 2.06 (2H,CF2CH2), 1.84 (2H, CH2CH2Br), 1.60 (2H, CF2CH2CH2), 1.45 (4H, CF2CH2CH2CH2CH2); mp=35-37° C.

Provenance & Evidence