3-ethyl-2-methyl- -trifluoromethanesulfonate

Abbreviations Ac acetyl Bn benzyl Cu(OTf)2 copper triflate Et ethyl HOTf trifluoromethanesulfonic acid KHMDS potassium hexamethyldisilazane Kim potassium imidazole / Hx / Hexyl Me methyl ... 

Boron azaenolates, generated from achiral 2-ethyl-4,5-dihydro-4,4-dimethyloxazolc (10) and chiral diisopinocamphcylboryl trifluoromethanesulfonate [14, derived from (+)-a-pinene], selectively provide the //////-adducts (>90%) in 77 85% ee. These are converted to the corresponding methyl esters 16 in 22 -36% overall yield20,21. 

Recently, there has been considerable interest in developing molten salts that are less air and moisture sensitive. Melts such as l-methyl-3-butylimidazolium hexa-fluorophosphate [211], l-ethyl-3-methylimidazolium trifluoromethanesulfonate [212], and l-ethyl-3-methylimidazolium tetrafluoroborate [213] are reported to be hydro-phobic and stable under environmental conditions. In some cases, metal deposition from these electrolytes has been explored [214]. They possess a wide potential window and sufficient ionic conductivity to be considered for many electrochemical applications. Of course if one wishes to take advantage of their potential air stability, one loses the opportunity to work with the alkali and reactive metals. Further, since these ionic liquids are neutral and lack the adjustable Lewis acidity common to the chloroaluminates, the solubility of transition metal salts into these electrolytes may be limited. On a positive note, these electrolytes are significantly different from the chloroaluminates in that the supporting electrolyte is not intended to be electroactive. 

DIKETONES l-Benzyl-4-(2-hydioxy-ethyl)-5-methyl-l, 3-thiazolium chloride. Copper(II) trifluoromethanesulfonate. 

In some procedures, thioacetal cleavage occurs after alkylation at the sulfur atom with a reactive alkylating reagent such as methyl iodide, tnalkyloxonium tetrafluoroborate (Meerwein salt), or ethyl trifluoromethanesulfonate to give a tnalkylsulfonium salt. 

Bis(cyclopentadienyl)dichlorozirconium(lI). Chlorotris(isopropoxy)titanium. Di-n-butylboryl trifluoromethanesulfonate. (4S, 5S)-2-Ethyl-4-(methoxymethyl)-5-phenyloxazoline Methyl O-me thy lactate. 2-Methyl-2-trimethylsilyloxypentane-3 one. Morpholine-Camphoric acid. Tin. Tin(II) trifluoromethanesulfonate. 

SILYLATION Bis(trimethylsilyl)urea. t-Butyldimethylchlorosilane. t-Butyldimethylsilyl trifluoromethanesulfonate. Chlorotrimethylsilane. Dimethyl(2,4,6-tri-f-butylphenoxy)chlorosilane. Ethyl trimethylsilylacctate. Ketene t-butyldimethylsilyl methyl acetal. N-Methyl-N-(/-... 

Methyl and ethyl trifluoromethanesulfonates were used to alkylate dimethyl tellurium9,10. When a compound with two organotelluro groups linked by a chain of methylene groups is treated with methyliodide in acetone, both tellurium atoms are methylated11. 

Related Reagents. (5,5)-2,2 -(Dimethylmethylene)bis-(4-/-butyl-2-oxazoline) Bis(dimethylglyoximato)(methyl)(pyridine)-cobalt(III) Copper(II) Trifluoromethanesulfonate (15,95)-1,9-Bis [(/-butyl)dimethylsilyloxy]methyl -5-cyanosemicorrin (5)-2-[2-(Diphenylphosphino)phenyl]-4-phenyloxazoline Ethyl Diazoacetate. 

Abbreviations Ac acetyl AIBN azobisisobutyronitrile All allyl Bn benzyl Bz benzoyl ClAc chloroacetyl DAST diethylaminosulfur trifluoride DBU l,8-diazabicyclo[5.4.0]-undec-7-ene DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTST dimethyl(methylthio)sulfonium trifluoromethanesulfonate Fmoc 9-fluorenyl-methoxycarbonyl HDTC hydrazine dithiocarboxylate IDCP iodonium di-collidine perchlorate Lev levulinoyl MBz 4-methylbenzoyl Me methyl MEK methyl ethyl ketone MP 4-methoxyphenyl NBS iV-bromosuccinimide NIS A-iodosuccinimide Pent n-pentenyl Pfp pentafluorophenyl Ph phenyl Phth phthaloyl Piv pivaloyl PMB 4-methoxybenzyl TBAF tetrabutylammonium fluoride TBDMS tcrt-butyldimethylsilyl TBDPS tert-butyldiphenylsilyl TCA trichloroacetyl TES triethylsilyl Tf trifluoromethanesulfonyl TMS trimethylsilyl Tol 4-methylphenyl Tr trityl Troc 2,2,2-trichloroethoxycarbonyl Ts tosyl. 

An improved and convenient preparation of pyrimidines and condensed pyrimidines from ketones and nitriles was reported. In the presence of acetonitrile, the cation generated from methyl ethyl ketone with trifluoromethanesulfonic anhydride is trapped by the nucleophile, whereby a resonance-stabilized nitrilium species is formed. A second molecule of nitrile reacts with nitrilium intermediate, and after elimination of triflic acid, cyclization, and loss of a proton, the pyrimidine product was obtained in a useful yield. The formation of pyrimidines is accompanied by a minimum... 

Addition by the Heterocycle. Under Heck conditions, 3-phenyM-vinyltbiophenes 86 were formed from 3-iodo-4-phenylthiophene and ethyl vinyl ketone, methyl acrylate, and m-nitrostyrene (Scheme 37) 4-Iodo-3-trimethylsilylfuran under similar Heck conditions with alkenes reacted in two regioselecUve manners. Alkenes with electron- withdrawing groups, such as methyl vinyl ketone and ethyl acrylate, gave exclusively tron -substituted alkenes 87. AEyl alcohol, styrene, and 4-methylstyrene gave a,a-disubstituted products 88.t" l-(Phenylsulfonyl)indol-3-yl trifluoromethanesulfonate under Heck conditions provides 3-vinylindoles 89. " An excellent yield was reported for the reaction between the triflated deaza nucleoside 90 and ethyl acrylate. ... 

Draw the structure and give the name of the sulfonic acid precursors to ethyl henzenesulfonate, methyl methanesulfonate, and 1-methylethyl trifluoromethanesulfonate. 

One-carbon Homologation of Carboxylic Acids. l-[(Tri-methylsilyl)methyl]benzotriazole converts benzoyl chlorides to the corresponding (benzotriazol-l-yl)methyl aryl ketones in high yields (see eq 1). Treatment with triflic anhydride and 2,6-lutidine in CH2CI2 converts these ketones into their enolate triflates in 83-95% yields (eq 4). In the subsequent steps, the triflates are treated with sodium methoxide and then with ethanolic HCl to afford ethyl esters of the corresponding arylacetic acids in 89-98% yields (eq 5). The proposed reaction mechanism involves elimination of trifluoromethanesulfonic acid with sodium methoxide and final alcoholysis of the obtained l-(arylethynyl)benzotriazole intermediates with ethanolic HCl. A comparable classical method for one-carbon homologation of carboxylic acids, the Amdt-Eistert reaction, involves difficult to handle diazomethane and Q -diazoketones. ... 

It has been estimated that vinyl cation, CH2=CH, lies between ethyl cation and methyl cation in its stability. The intermediacy of substituted vinyl cations in solvolysis reactions has been demonstrated, but no evidence has yet been presented for their direct observation by NMR. Even the addition of stabilizing substituents such as methoxyphenyl has failed to yield observable vinyl cations. Vinyl cations are, however, intermediates in solvolysis reactions involving very good leaving groups, specifically trifluoromethanesulfonates (triflates). The products of such reactions are allenes, acetylenes, and vinyl esters. For both trifluoroacetic acid and acetic acid solvolysis the vinyl esters are mixtures of Z and E isomers, ruling out a stereospecific substitution." ... 

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