tert-Butyldimethylsilyl chloride

Description

tert-Butyldimethylsilyl chloride (TBS-Cl) is generally used as a reagent for installing TBS protecting groups. A similar reagent is tert-butyldimethylsilyl trifluoromethanesulfonate (TBS-OTf).

Chemical properties

tert-Butyldimethylsilyl chloride is a colorless or white solid that is soluble in many organic solvents but reacts with water and alcohols.It is an organosilicon compound that can be used as a versatile protecting reagent for alcohols, amines, amides, and various carboxylic acids.

The Uses of tert-Butyldimethylsilyl chloride

Tert-butyldimethylsilyl chloride (TBDMSCl) is a protective organosilicon agent used in drug synthesis. It protects hydroxyl groups in ribonucleosides, acts as an oxidant and decyanide, and aids in making prostaglandins and hypolipaemic drugs. It's also key in synthesizing isoxazolines N-oxides and serves as a general protecting reagent for amines, amides, and alcohols. TBDMSCl traps anions, exemplified by its efficiency in capturing the lithio α-phenylthiocyclopropane anion. It also converts primary and secondary nitriles into C,N-disilyl- and Nsilylketenimines with high yields. Furthermore, TBDMSCl is used to prepare silyl stannanes by trapping tin anions, which react with alkynes to form cis-silyl stannylalkenes in good yields when catalyzed by tetrakis(triphenylphosphine)palladium(0).

Definition

ChEBI: Tert-butyldimethylsilyl chloride is a silyl chloride consisting of a central silicon atom covalently bound to one chloro, one tert-butyl and two methyl groups. tert-Butyldimethylsilyl chloride is a derivatisation agent used in gas chromatography/mass spectrometry applications. It has a role as a chromatographic reagent.

Preparation

tert-butyldimethylsilyl chloride (TBSCI) was synthesized by the reaction of tert-butyllithium with dichlorodimethylsilane.
The pentane solution of dichlorodimethylsilane was cooled to 0°C, and the pentane solution of tert-butyllithium was added dropwise with stirring under nitrogen. The temperature was maintained at 0 °C, stirred for 1.5 h and then heated to 25 °C, and the reaction was continued for 48 h. Distillation, collect 125 ℃ (97.5kPa) fractions, stand to solidify, and obtain tert-butyldimethylsilyl chloride. Yield 70%.

Reactions

tert-Butyldimethylsilyl chloride reacts with alcohols in the presence of base to give tert-butyldimethylsilyl ethers:
(Me3C)Me2SiCl + ROH → (Me3C)Me2SiOR + HCl
These silyl ethers hydrolyze much more slowly than the trimethylsilyl ethers.

Hazard

Moderately toxic.

Flammability and Explosibility

Flammable

Purification Methods

Fractionally distil it at atmospheric pressure. [Sommer & Tyler J Am Chem Soc 76 1030 1954, Corey & Venkateswarlu J Am Chem Soc 94 6190 1972, Beilstein 4 IV 4076.]