4-Tolyl triflate

An interesting new addition to the methods available for constructing arylthiophenes is the addition of thienyllithium to arynes generated from aryl triflates and LDA <93JOC4722>. Both ipso-and c/ne-substitution are possible. o-Tolyl triflate gave the ortho- and we/a-substituted products in the ratio 43 57, but 2-methoxyphenyl triflate gave exclusively the weta-substituted product. 

When the rigid tridentate ligand l,3,5-tri-3-pyridyl-2,4,6-tri-/)-tolyl-benzene (3) was reacted with silver(I) triflate or silver hexafluorophosphate, cage-like... 

It was shown that palladacycles 1, prepared from palladium(II) acetate and the tris(a-tolyl)- or trimesitylphosphane, are excellent catalysts for the Heck coupling of triflates and halides (including certain aryl chlorides). In this case, oxidation states -l-U and +IV appear to be involved in the catalytic cycle [16]. 

The electrochemical properties of a number of isostructural rhe-nium(V) oxo, rhenium(V) imido, osmium(VI) nitrido, of formula [M(E)(X)(Y)(Tp )] (Tp = Tp or Tp, E = O, N-tolyl, N X, Y = hydrocarbyl, halide, triflate), have been described. The reactivity of these complexes as inner-sphere oxidants does not correlate with their peak reduction potentials, whereas the ease of the oxidation of these compounds well parallels their reactivity as oxidants.206... 

MMTS MsOH NBS NHMDS NMP NMR PPb Ph Pr PTC rt TBDMS Tf THF THP TLC TMEDA TMS TMSOTf Tol TOMAC Ts TsOH UDP methyl methylthiomethyl sulfoxide (=FAMSO) methanesulfonic acid N-bromosuccinimide sodium hexamethyldisililazide /V-methyl-2-pyrrolidone nuclear magnetic resonance parts per billion phenyl propyl Phase transfer catalysis room temperature t-butyldimethylsilyl triflatc (trifluoromethanesulfonate) tetrahydrofuran 2-tetrahydro-2//-pyran-2-yl thin-layer chromatography /V./V./V /V -tetramethylethylenediamine trimethylsilyl trimethylsilyl triflate p-tolyl trioctylmethylammonium chloride tosyl p-toluenesulfonic acid ultrasonically dispersed potassium... 

Other nickel-catalyst systems were also demonstrated to catalyse amina-tion of phenol derivatives, such as Ni(COD)2/SIPr-catalysed amination of aiyl carbamates, Ni(COD)2/dppf-catalysed amination of aryl sulfamates, and (dppf)Ni(o-tolyl)Cl-catalysed amination of aiyl sulfamates, mesylates, and triflates/ ... 

Once again, the nickel-catalysed reactions are far more sensitive to the steric encumbrances, than the palladium-catalysed analogues. Aryl triflates and related sulfonates can serve as the electrophilic reactants in the Kharasch reactions in the presence of an equimolar amount of lithium bromide. The latter additive is a reagent for triflate-bromide exchange, which became a very fast reaction under the Kharasch reaction conditions, since the nickel and palladium-catalysed nucleophilic substitutions of aryl halides and sulfonates are well established reactions, see Chapter 3. In this manner, 2-biphenyl triflate (135) was reacted with 4-tolylmagnesium bromide (136) to give 2-(4-tolyl)biphenyl (137) with a 93% yield [40], respectively. Scheme 8. 

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