Trimethylsilyl trifluoromethanesulfonate

Koiuradsson, R Udodong, U.E. Fraser-Reid, B., Tetrahedron Lett. 1990, 37,4313. 

Lewis Acid Catalyst. Jefford has reported that condensation reactions of 2-trimethylsiloxyfuran with aldehydes can he catalyzed by Et3SiOTf to give mainly Ihe threo addition producl (eq 8). Conversely, Ihe erythro adducl is favored when fluoride ion is used as the catalyst. 

Fraser-Reid has reported that an equimolar mixture of A -iodosuccinimide and EtsSiOTf efficiently promotes the glyco-sylation of hindered glycoside donors with -pentenyl glycoside acceptors (eq 9).  

InChIKey = FTVLMFQEYACZNP-UHFFFAOYSA-N Alternate Name TMSOTf. 

Solubility sol aliphatic and aromatic hydrocarbons, haloalkanes, ethers. 

TMS enol ethers may be prepared by rearrangement of a-ketosilanes in the presence of catalytic TMSOTf (eq 6).  

Form Supplied in colorless liquid commercially available. Preparative Methods may be prepared by a variety of methods. Handling, Storage, and Precautions flammable corrosive very hygroscopic. 

Silylation. TMSOTf is widely used in the conversion of carbonyl compounds to their enol ethers. The conversion is some 10 faster with TMSOTfITriethylamine than with Chlorotrimethyki- 

Enhanced regioselectivity is obtained when trimethylsilyl enol ethers are prepared by treatment of a-trimethylsilyl ketones with catalytic TMSOTf (eq 7).  

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Trichloroacetonitrile reacts with glycosidic hydroxy groups of protected sugars to form glycosyl trichloroacetimidates (R. R. Schmidt, 1980, 1984,1985,1986 B. Wegmann, 1988). The imidate is substituted by alcohols in the presence of trimethylsilyl trifluoromethanesulfonate... 

The chlorosilanes are clear Hquids that should be treated as strong acids. They react readily with water to form corrosive HCl gas and Hquid. Liquid chlorosilanes and their vapors are corrosive to the skin and extremely irritating to the mucous membranes of the eyes, nose, and throat. The nitrogen-functional silanes react with water to form ammonia, amines, or amides. Because ammonia and amines are moderately corrosive to the skin and very irritating to the eyes, nose, and throat, silylamines should be handled like organic amines. Trimethylsilyl trifluoromethanesulfonate and trimethylsilyl iodide form very corrosive acidic products. 

Opening by trimethylsilyl trifluoromethanesulfonate yields an adduct (54) from which trifluoromethanesulfonic acid can be eliminated to give an allylic alcohol (Scheme 47) (79JA2738) [cf. base-promoted isomerization to allylic alcohols (Section 5.05.3.2.2)]. 

Trimethylsilyl trifluoromethanesulfonate. This is an extremely powerful silylating agent, but probably is more useful for its many other applications in synthetic chemistry... 

Trimethylsilyl trifluoromethanesulfonate (trimethylsilyl triflate) is the most synthetically useful representative of the family of trialkylsilyl perfluoroalkane-sulfonates (for a review, see reference 101) This reagent is commercially available or can be prepared easily by the reaction of chlorotrimethylsilane and triflic acid [101] It has wide application in organic synthesis as an excellent silylating reagent... 

Very few 1-unsubstituted 17/-azcpines have been isolated and, as a consequence, substitution at nitrogen is a rare event however, 1-mesyl-l//-azepine (8) and l-(trimethylsilyl)-l //-azepine (9) can be obtained by treating 1//-azepine (7) with mesyl chloride and with trimethylsilyl trifluoromethanesulfonate, respectively.9... 

Considerable efforts have been devoted to the stereoselective introduction of a /(-methyl function in intermediates for the synthesis of 1 jS-methylcarbapenems. While the trimethylsilyl trifluoromethanesulfonate catalyzed reaction of a 4-acetoxyazetidinone derivative with ketene acetals shows no selectivity, ketene thioacetals lead to stereoselective formation of the a-methyl isomer108. The zirconium enolate, however, shows high /(-methyl selectivity. 

High enantioselectivities may be reached using the kinetic controlled Michael addition of achiral tin enolates, prepared in situ, to a,/i-unsaturated carbonyl compounds catalyzed by a chiral amine. The presence of trimethylsilyl trifluoromethanesulfonate as an activator is required in these reactions236. Some typical results, using stoichiometric amounts of chiral amine and various enolates are given below. In the case of the l-(melhylthio)-l-[(trimethylsilyl)thio]ethene it is proposed that metal exchange between the tin(II) trifluoromethanesulfonate and the ketene acetal occurs prior to the 1,4-addition237,395. 

This method is especially useful for the conversion of ketones to ketals, since the direct reaction of a ketone with an alcohol often gives poor results. In another method, the substrate is treated with an alkoxysilane ROSiMe3 in the presence of trimethylsilyl trifluoromethanesulfonate. ... 

Treatment of the enantiopure substrate 4-341 containing a sila-ene moiety with trimethylsilyl trifluoromethanesulfonate (TMS OTf) gave 4-342 in a highly stereoselective fashion and 52% yield. It can be assumed that the reaction passes through the two chairlike transition structures 4-345 and 4-346 (Scheme 4.76). It is of interest that the stereochemistry of the two C-C-double bonds in 4-341 did not influence the configuration of the product. Moreover, when using EtAlCl2 as mediator, a 3 l-mixture of 4-343 and 4-344 is obtained in 40% yield. This can be explained by an axial orientation of the carbonyl moiety in the transition state. 

There are relatively few entries in the non-fused dioxepin area, and most of these focus on reactions of these systems. For example the triflic acid-initiated polymerisation of 1,3-dioxepane in the presence of acetic acid and hexanedicarboxylic acid has been studied and mechanistic aspects discussed <00JPS(A)1232>. Biodegradable microspheres for the controlled delivery of drugs have been made from copolymers and homopolymer blends of L-lactide and l,5-dioxepan-2-one <00PP1628>. Ring contraction of 5-methylene-l,3-dioxepanes (eg. Ill) on reaction with trimethylsilyl trifluoromethanesulfonate in the presence of base afforded the exo tetrahydropyrans, in good yields <00TL2171>. 

A diastereoselective synthesis of /3-(iV-acylamino)aldehydes was accomplished via ruthenium-catalyzed isomerization of 0-vinyl-iV,0-acetals followed by rearrangement in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) (Scheme 36).63... 

TMSOTf—trimethylsilyl trifluoromethanesulfonate Troc—trichloroethoxycarbonyl Trt—trityl... 

In addition to the example depicted in Scheme 20.40 and examples involving a prototropic rearrangement [61], the use of trimethylsilyl trifluoromethanesulfonate to induce the transformation of 212 afforded 213 bearing a keto substituent at the allenic terminus (Scheme 20.44) [81]. Thermolysis of 213 promoted the Myers-Saito cyclization leading to 216. 

CAUTION Many organotin compounds are known to be highly toxic 2 (Note 1), and hydrogen bromide (HBr), titanium tetrachloride (TiCi4), and trimethylsilyl trifluoromethanesulfonate (TMSOTf) are corrosive. Steps A-C should be performed in an efficient fume hood while wearing gloves and adequate eye protection. 

Trimethylsilyl trifluoromethanesulfonate was obtained from the Aldrich Chemical Company, Inc., and was purified by distillation under nitrogen (bp 142°C/760 mm), immediately prior to use. 

Trimethylsilyl trifluoromethanesulfonate Methanesulfonic acid, trifluoro-, trimethyIsilyI ester (8,9) (27607-77-8)... 

Bicyclo[2.2.1]hepta-2,5-diene-l,4-bis(diphenylphosphino)butanerhodium trifluoromethanesulfonate Rhodiura(l+), [(2,3,5,6- )-bicyclo[2.2.1]hepta-2,5-diene][l, 4-butanediylbi s[diphenyl phosphine]- ,P ]-, tri f1uoromethanesulfonate Bicyclo[2.2.l]hepta-2,5-diene-2,4-pentanedionatorhodiurn Rhodium, (2,5-norbornadiene) (2,4-pentanedionato)- (8) Rhodium, [(2,3,5,6- )-bicyclo[2.2.l]hepta-2,5-diene] (2,4-pentanedionato-0,0 )- (9) (32354-50-0) Trimethylsilyl trifluoromethanesulfonate Methanesulfonic acid, trifluoro-, trimethylsilyl ester (8,9) (27607-77-8)... 

A special case is the ring-forming reaction in the lactone acetal 568,69. When 5 is treated with trimethylsilyl trifluoromethanesulfonate (trimethylsilyl triflate TMSOTf) in the presence of triethylamine at 0°C the cisjtrans mixture 6a and 6b is formed in ca. 50% yield. In this intramolecular aldol reaction the probable intermediate is the oxonium ion 7. 

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