Trifluoromethanesulfonic Acid, Chlorobis (1,1-dimethylethyl)silyl ester

Physical properties

bp 60 °C/0.3 mm Hg.

The Uses of Trifluoromethanesulfonic Acid, Chlorobis (1,1-dimethylethyl)silyl ester

Trifluoromethanesulfonic Acid, Chlorobis (1,1-dimethylethyl)silyl Ester is a reagent used for the preparation of unsymmetrically substituted silaketals t-Bu2Si(OR1)(OR2) and other silicon compounds of type t-Bu2SiXY.
1.Unsymmetrical Silaketal Formation. Silicon tethers are very commonly used to convert intermolecular into intramolecular reactions.

Preparation

trifluoromethanesulfonic acid chlorobis (1,1-dimethylethyl)silyl ester can be prepared on a medium scale as follows:1 Di-t-butylchlorosilane (25.0 g, 140 mmol) was stirred at ?15??C in a flask equipped with a dropping funnel and thermometer. Triflic acid (24 mL, 40.6 g, 270 mmol) was added at a rate sufficient to maintain the temperature below ?15??C. After complete addition, the cooling bath was removed and the reaction mixture was stirred at 25??C overnight. The crude reaction mixture consisted of a t-Bu2Si(Cl)OTf (1H NMR: |? = 1.19) and t-Bu2Si(H)OTf (|? = 1.12) in a 91:9 ratio. The crude product was purified by distillation using a spinning band column yielding 24.0 g (53%) of 1. Under the chosen reaction conditions, no subsequent displacement of chloride to produce t-Bu2Si(OTf)2 was observed.This substitution process is slow and would require elevated temperatures.