R3SiOTf

R3SiOTf refers to a family of organosilicon compounds in which a silyl group, represented as R3Si–, is bonded to an oxytriflate fragment (–OTf), where Tf denotes the trifluoromethanesulfonyl group. The general structure is R3Si–O–SO2CF3. These compounds are strong silylating agents and, in many cases, also act as Lewis acids. They are widely used in organic synthesis to activate alcohols, protect alcohols as silyl ethers, and promote various electrophilic or dehydration-type transformations.

Common representatives include trimethylsilyl triflate (TMSOTf) and tert-butyldimethylsilyl triflate (TBSOTf). R groups can be alkyl or aryl, leading to a range of reagents with differing steric and electronic properties. As a class, R3SiOTf reagents are typically moisture sensitive and require handling under strictly anhydrous, inert conditions. They are usually liquids or low-melting solids, and their reactivity can be tuned by the choice of R groups.

Preparation typically involves metathesis between a corresponding silyl chloride (or hydride source) and a silver or other salt of triflic acid, for example reacting a silyl chloride with AgOTf to give R3SiOTf and AgCl as a byproduct. Alternatives include other halide/triflate exchange methods under dry conditions.

Applications span protection of hydroxyl groups as silyl ethers, activation of alcohols for substitution or glycosylation reactions, and Lewis-acid-promoted transformations in complex organic syntheses. Due to their high reactivity, these reagents require careful handling to avoid hydrolysis and corrosive exposure to triflic acid.

See also: trimethylsilyl triflate, tert-butyldimethylsilyl triflate, silyl ethers, glycosylation activators.