ROSiMe3

ROSiMe3 denotes a trimethylsilyl ether, a class of organosilicon compounds in which a hydroxyl group of an alcohol is protected by the trimethylsilyl group: RO–Si(CH3)3. The R group is derived from the corresponding alcohol (alkyl or aryl). In shorthand, these species are written as RO-SiMe3. They are among the most common protecting groups for alcohols in organic synthesis.

Installation and general use: A typical route to RO-SiMe3 involves silylation of ROH with chlorotrimethylsilane (Me3SiCl) in the presence of a base such as imidazole or a tertiary amine, in an aprotic solvent. Alternative silylation reagents include various silyl chlorides or triflates. The resulting trimethylsilyl (TMS) ethers are easy to install and are favored when a simple, readily removable protecting group is desired.

Deprotection and stability: RO-SiMe3 groups can be cleaved to regenerate the free alcohol ROH by treatment with fluoride sources (for example, tetrabutylammonium fluoride, cesium fluoride, or HF-pyridine) or under certain acidic conditions. They are relatively labile compared with more hindered silyl ethers, which makes them convenient for short synthetic sequences but less suitable when harsh conditions are anticipated. TMS ethers are typically stable to neutral or mildly basic conditions but sensitive to moisture, strong acids, and fluoride reagents.

Applications and context: ROSiMe3 compounds are widely used as protecting groups for primary and secondary alcohols during multi-step syntheses. Their use allows selective reactions at other functional groups while the alcohol is temporarily masked, with straightforward deprotection to restore the alcohol at the end of a sequence.