Trimethylsilyl group

This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications.

Chemists sometimes use a trimethylsilylating reagent to derivatize rather non-volatile compounds such as certain alcohols, phenols, or carboxylic acids by substituting a trimethylsilyl group for a hydrogen in the hydroxyl groups on the compounds.

In an NMR spectrum, signals from atoms in trimethylsilyl groups in compounds will commonly have chemical shifts close to the tetramethylsilane reference peak at 0 ppm.

[1] Otherwise very reactive molecules can be isolated when enveloped by bulky trimethylsilyl groups.

With a van der Waals volume of up to 7 cubic angstrom it surpasses the related TIPS group (around 2)[2][3] and one potential application is its use as a temporary substituent promoting asymmetric induction for example in this diastereoselective one-pot reaction involving two sequential Mukaiyama aldol reactions:[4] TTMSS can also stand for tris(trimethylsilyl)silane,[5][6] which is comparable as a chemical reagent to tributyltin hydride without the associated toxicity concern of organotin and tributyltin compounds.