Triethylsilyl trifluoromethanesulfonate

Aziridination Reactions. Metal nitrenes are also known to undergo aziridination of alkenes7 Copper-catalyzed aziridina-tions of styrene derivatives have thus been reported using 2,2,2-trichloroethyl-TV tosyloxycarhamate as a nitrene precursor (eq 6).  

In contrast to other methods, free aziridines can he produced in good yields using mild basic reaction conditions (eq 7). 

Solubility readily sol hydrocarbons, dialkyl ethers, halogenated solvents. CH2CI2 is employed most commonly. Reactions in 1,2-dichloroethane proceed faster than those in CCLj or Et20. Protic solvents and THF react with trialkylsilyl triflates and are therefore not suitable. 

Preparative Methods can be prepared by reacting chlorotri-ethylsilane with trifluoromethanesulfonic acid followed by distillation.  

Handling, Storage, and Precautions trialkylsilyl triflates are generally corrosive and moisture sensitive. Appropriate precautions should be taken to ensure that the reagent is handled and stored under rigorously anhydrous conditions. 

Secondary and tertiary alcohols can be silylated under mild conditions using EtsSiOTf and 2,6-lutidine or a trialkylamine as a proton scavenger (eqs 1 and 2).  

Silyl enol ethers can be conveniently prepared by treatment of ketones with Et3SiOTf and triethylamine (eq 3). Similarly, esters can be converted to silyl ketene acetals however, large amounts of the C-silylated product may also be isolated (eq 4). EquiUbration of O- and C-silylated products may occur in the presence of catalytic amounts of EtsSiOTf.  

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The selective activation of glycoside trichloroacetimidates over phenyl selenoglycosides was also demonstrated by glycosidation of phenyl seleno-glycoside acceptors 168 and 169 with glycosyl trichloroacetimidate 172. In the presence of catalytic amounts of triethylsilyl trifluoromethanesulfonate at -78°C, the disaccharide derivatives 170 and 171 were obtained in respectively 84 and 90% yields. 

For direct coupling, which is the most widely used procedure, the promoter of choice is AModosuccinimide (NIS) in the presence of triethylsilyl trifluoromethanesulfonate [148]. Under these conditions the reaction is very fast, while the use of NIS or N-bromosuccinimide without acid catalyst slows down the coupling rate. The effect of triflic acid or silyl triflate on NIS is shown in Scheme 28. 

In addition the selective activation of both glycosyl trichloroacetimidates (using catalytic triethylsilyl trifluoromethanesulfonate at —78 °C) and glycosyl bromides (using silver trifluoromethanesulfonate and collidine) over selenoglycosides can be achieved. 

Fluoride-Based Desilylation. Treatment of symmetrical 0,0-acetals with triethylsilyl trifluoromethanesulfonate in the presence of 2,4,6-collidine yields weakly electrophilic collidinium... 

The diastereoselectivity of the reaction of TMSOF with aldehydes can be controlled by the choice of catalyst. Lewis acids such as triethylsilyl trifluoromethanesulfonate (TESOTf), BF3-OEt2, and tin(IV) chloride favor yn-selectivity, while the use of fluoride ion confers anti-selectivity (eq S). In both situations, open... 

Related Reagents. r-Butyldimethylchlorosilane r-Butyl-dimethylsilyl Trifluoromethanesulfonate Chlorotrimethylsilane Chlorotriphenylsilane Triethylsilyl Trifluoromethanesulfonate Trimethylsilyl Trifluoromethanesulfonate. 

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