Trimethylsilyl trifluoromethanesulphonate

THF THP TIPS TIPSOTf TMEDA TMS TMSC1 TMSCN TMS I TMSOTf Ts tetrahydrofuran tetrahydropyranyl tri-isopropylsilyl tri-isopropylsilyl trifluoromethanesulphonate AVV,N N -tetramethylethylenediamine trimethylsilyl trimethylsilyl chloride (chlorotrimethylsilane) trimethylsilyl cyanide (cyanotrimethylsilane) trimethylsilyl iodide (iodotrimethylsilane) trimethylsilyl trifluoromethanesulphonate tosyl (p-tolucnesulphonyl)... 

The reaction of 4-acetoxyazetidin-2-one with enolate anions is difficult, but now a high-yield equivalent has been introduced. This involves the reaction of 0-silylated enolates and 4-acetoxy-1-trimethylsilyloxyazetidin-2-one (25) in the presence of trimethylsilyl trifluoromethanesulphonate. ... 

Trimethylsilyl trifluoromethanesulphonate is useful as a removable group for the activation of imines by conversion into iminium salts the reagent forms complexes with... 

Two further reactions might be included here, since they involve modification at both carbon and sulphur. In the first reaction, dehydration of the sulphoxides 388 (R = Me or aryl R = H, Me, ethenyl or Ph) to the diethyl [(l-alkylthio)alk-l-enyl]phosphonates 389 is said to result following the action of trimethylsilyl trifluoromethanesulphonate The second reaction constitutes a new and improved synthesis of an ester of (mercap-tomethyl)phosphonic acid, and consists in the treatment of methyl (diisopropylphosphi-noyl)dithioformate with NaBH4. ... 

Uses. It was shown that a mixture of solutions of triphenylcarbinol and trimethylsilyl trifluoromethanesulphonate in an equimolar proportion may be used as a reagent for the effective tritylation of a secondary hydroxyl group. [PMID 10923195]. 

The mechanism of the Friedel-Crafts-catalysed Hilbert-Johnson reaction has been reviewed, with particular reference to the reaction of silylated uracils and stannic chloride or trimethylsilyl trifluoromethanesulphonate. ... 

Dibromomalonates have been recommended as good sources of bromonium ions in the preparation of a-bromoesters from ester enolates. Trimethylsilyl trifluoromethanesulphonate is useful for the preparation of a-trimethylsilyl esters directly from esters.Little of the corresponding silyl enolate is formdd. 

Pd(II)Cl2 and trimethylsilyl trifluoromethanesulphonate as alternative catalysts plus 1,4-additions to the aza-dienes were also described. Furthermore, it has been shown that dehydrogenation of secondary amines with phenylseleninic anhydride (or the acid) can... 

The bicyclo[2,2,l]heptane system also continues to find employment for the assessment of new synthetic procedures, or for testing the efficacy of new reagents. Isolated yields of 50—65 % of ap-unsaturated aldehydes have been obtained by reaction of alkyl tosylhydrazones with butyl-lithium, addition of DMF, and hydrolysis however, reaction of camphor tosylhydrazone (381 X = NNHTs) according to this procedure only gave 10 % of the aldehyde (382 X = CHO), presumably because of unfavourable steric effects. " Trimethylsilyl trifluoromethanesulphonate is a mild reagent for converting carbonyl compounds into trimethylsilyl enol ethers, for example the production of (382 X = OSiMcj) from camphor (381 X = Experimental details... 

Several new procedures for isomerization of oxirans to allylic alcohols have been published. Aluminium isopropoxide has been used on some polyprenyl epoxides (Scheme 12). Trimethylsilyl trifluoromethanesulphonate and base... 

The reduction of aldehydes by pyridine-borane is a novel route to either symmetrical ethers or, in the presence of an appropriate alcohol, to unsym-metrical ethers (Scheme 41).Trimethylsilyl trifluoromethanesulphonate is the... 

A publication surveying uses of trimethylsilyl trifluoromethanesulphonate in synthesis includes the isomerization of epoxides to give allylic alcohols cf. 4, 145) in unsymmetrical cases ring opening occurs at the more substituted epoxide carbon atom (Scheme 14), and the same regiochemistry is observed in... 

The reaction of allyltrimethylsilane with acetals to give homoallylic ethers, previously conducted with stoicheiometric amounts of Lewis acids, has now been shown to proceed in high yield under very mild conditions with catalytic quantities of trimethylsilyl trifluoromethanesulphonate. No reaction could be achieved with aldehydes (or ketones) in place of the acetals. By contrast, 3-chloroallyltrimethylsilane reacts with aromatic and aliphatic aldehydes, though not with ketones, in the presence of Lewis acids, to give methyl ethers of homoallylic alcohols (e.g. Scheme 67), a process involving an unusual methyl group transfer. 

Aldehydes and ketones are readily acetalized by alkoxysilanes under aprotic conditions in the presence of trimethylsilyl trifluoromethanesulphonate as catalyst,and anhydrous aluminium chloride has been found to be an efficient reagent for promoting thioacetalization of carbonyl compounds. Monothiols reacted with highly enolizable carbonyl compounds to give mainly the vinyl sulphide under these conditions. 1,3-Dicarbonyl compounds react with propane-... 

Silyl enol ethers serve as precursors to a variety of -(substituted methyl) ketones (Scheme 54). Trimethylsilyl trifluoromethanesulphonate catalyses the formation of a-alkoxymethyl ketones from dialkoxymethanes in the presence of a sterically hindered nitrogen base, and titanium tetrachloride catalyses the site-specific ureidoalkylation of silyl enol ethers of cycloalkanones by reaction with chloromethyl carbamates. Mannich dimethylaminomethylation can be... 

The reaction of silyl enol ethers and acetals to form aldol products has been accomplished by the use of trimethylsilyl trifluoromethanesulphonate as catalyst [equation (47)]. No polycondensation, self-condensation, or enone products were observed. When chiral centres were formed, there was a high stereoselectivity for the erythro-adducXs, irrespective of the geometry of the silyl enol ether,... 

In a recent study, the reaction of allyltrimethylsilane with acetals to produce homoallylic ethers with allyl inversion, which is known to be mediated by various Lewis acids such as TiCU (1,179), has been performed with catalytic amounts of trimethylsilyl trifluoromethanesulphonate at low temperatures, according to... 

General Synthesis and Reactions of Esters.— Esters and lactones are formed from ketones under aprotic conditions, using bis(trimethylsilyl) peroxide and a catalytic amount of trimethylsilyl trifluoromethanesulphonate yields for ten examples are between 24 and 76%. The reaction occurs specifically at the carbonyl group and carbon-carbon double-bonds are not affected. " Aldehydes are converted into methyl esters with a solution of sodium hypochlorite and methanol in acetic add yields of between 22 and 90% are obtained for seven examples. A similar reaction involves the treatment of an aldehyde with t-butyl hypochlorite followed by an alcohol yields are between 39 and 98% for six examples (Scheme 34). ... 

Allylic Alcohols. Full details have appeared of the conversion of epoxides into allylic alcohols, mediated by trimethylsilyl trifluoromethanesulphonate (Scheme 4) (see 6,163 4,145), and this sequence is mentioned in a review of trialkylsilyl perfluoroalkanesulphonates as reagents opening of an epoxide ring occurs at the more substituted centre. The use of trimethylsilyl iodide for the epoxide-allyl alcohol transformation (5, 158) is discussed in a review of the preparation and applications of this reagent. ... 

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