Trimethylsilyl trifluoromethanesulfonate (TMSOTf) is an organosilicon compound with the formula (CH3)3SiO3SCF3. 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.

Reactions

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 (CH3)3SiO3SCF3 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(SO2CF3) bond, the by-product being the highly volatile TMSCl which is easily removed.