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When attached to certain functional groups in a reactant molecule, trimethylsilyl groups may also be used as temporary protecting groups during chemical synthesis or some other chemical reactions. In chromatography, derivitization of accessible silanol groups in a bonded stationary phase with trimethylsilyl groups is referred to as endcapping.
Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH 3) 3 SiCl, often abbreviated Me 3 SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water.
The most important esters with common protecting-group use are the acetate, benzoate, and pivalate esters, for these exhibit differential removal. Sterically hindered esters are less susceptible to nucleophilic attack: Chloroacetyl > acetyl > benzoyl > pivaloyl Trimethylsilyl chloride, activated with imidazole, protects a secondary alcohol
Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R 1 R 2 R 3 Si−O−R 4 where R 4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis.
The protection mechanism begins with the base deprotonating the alcohol group. Next, the deprotonated alcohol group attacks the silyl atom of the silyl halide compound. The halide acts as a leaving group and ends up in solution. A workup step follows to remove any excess base within the solution. The overall reaction scheme is as follows:
These complexes are very labile so trimethylsilyl groups are again present for protection. These compounds are formed by reacting weaker alkylating agents (LiCH 3 and Mg(CH 3) 2 are too strong and lead to the formation of simple alkyls) with ClAn[N(Si(CH 3) 2] 3 (An = Th, U). a uranium-containing metallacycle
2-(Trimethylsilyl)ethoxymethyl chloride (SEM-Cl) is an organochlorine compound with the formula C 6 H 15 ClOSi, which was developed by Bruce H. Lipshutz during his work on the synthesis of N-methylmaysenine. It is used to protect hydroxyl groups, which can be cleaved with fluoride in organic solvents selectively under mild conditions. [1]
It is a colorless liquid that is soluble in diverse organic solvents, but reacts rapidly with moisture and solvents containing OH and NH groups. It is used in analytical chemistry to increase the volatility of analytes, e.g., for gas chromatography. [1] It is also used to introduce the trimethylsilyl protecting group in organic synthesis. [2]