Trimethylsilyl trifluoromethanesulfonate (TMSOTf) is an organosilicon compound with the formula . It is a colorless moisture-sensitive liquid. It is the trifluoromethanesulfonate derivative of trimethylsilyl. It is mainly used to activate ketones and aldehydes in organic synthesis.
TMSOTf is quite sensitive toward hydrolysis:
It is far more electrophilic than trimethylsilyl chloride.
Related to its tendency to hydrolyze, TMSOTf is effective for silylation of alcohols:
A common use of is for the preparation of silyl enol ethers. One example involves the synthesis of the silyl enol ether of camphor:
It was also used in Takahashi Taxol total synthesis and in chemical glycosylation reactions.
Trimethylsilyl trifluoromethanesulfonate has a variety of other specialized uses. It has been used to install tert-alkyl groups on phosphine (R = alkyl):
Deprotection of Boc-protected amines can be achieved using trimethylsilyl trifluoromethanesulfonate and triethylamine or 2,6-lutidine.
TMSOTf is also a useful reagent to replace metal-halogen bonds with a covalent M-O(SO<sub>2</sub>CF<sub>3</sub>) bond, the by-product being the highly volatile TMSCl which is easily removed.