chlorotrimethylsilane

Chlorotrimethylsilane, also known as trimethylsilyl chloride (TMSCl), is an organosilicon compound with the formula (CH3)3SiCl. It is a reactive chlorosilane widely used as a silylating agent in organic synthesis. The substance is a colorless, volatile liquid that hydrolyzes readily in the presence of moisture to give hydrogen chloride and trimethylsilanol, so it is stored under dry conditions and handled in a well-ventilated fume hood.

In chemical synthesis, TMSCl serves primarily to introduce the trimethylsilyl protecting group. It readily converts alcohols and phenols into their corresponding trimethylsilyl ethers in the presence of a base such as pyridine or imidazole. It also participates in the formation of silyl enol ethers from carbonyl compounds under basic conditions, a step used in enolate chemistry and aldol-type sequences. Additionally, it can react with amines and other nucleophiles to form silylated derivatives, and is widely used in carbohydrate and natural product synthesis as a mild protective or activating reagent.

Preparation and availability: TMSCl is commercially available and can be prepared industrially by chlorination of trimethylsilane or related chlorosilane routes. It is typically supplied as a colorless liquid or as a reagent-grade solution in anhydrous solvents.

Safety: It is corrosive and moisture sensitive. The reagent reacts with water and alcohols, releasing hydrogen chloride; proper personal protective equipment, a dry glassware setup, and an inert atmosphere are recommended. Store under inert gas in a tightly closed container away from moisture.