Electrolyte, supporting tosylate

Formation of allylic alcohols is favored by supporting electrolytes with tosylate anions. Scheme 7, [11], Under these conditions, only small amounts of ketone were produced. It has been suggested that the role of the tosylate is as a nucleophile that traps the carbocation. Elimination from this intermediate then leads to the allylic alcohol. This explanation is supported by isolation of the... 

Benzene hydrocarbons are known to undergo radical coupling reactions and the intramolecular reductive coupling of carbonyl compounds with a benzene ring has been achieved. Best conditions for this process are at a tin cathode with isopropanol solvent and tetaethylammonium tosylate as supporting electrolyte [102, 103], The reaction is performed at constant current in a divided cell. A single stereoiso-... 

Tetraalkylammonium tosylates [74] and trifluoromethanesulfonates [72] are also excellent electrolytes. Although tetraalkylammonium ions are favored as the cations for supporting electrolytes because of their wide potential range, other cations are sometimes used for special applications—for example, methyltri-phenyl phosphonium, whose tosylate is freely soluble in methylene chloride, and other fairly nonpolar solvents [74] or metal ions (lithium salts tend to have the best solubility in organic solvents) where undesirable reactions of the tetraalkylammonium ion might occur [13,75]. The properties of many electrolytes suitable for nonaqueous use have been surveyed [76]. 

Complexation constants for binding of mono- and di-negative oxoanions by the cryptands can be determined by pH-potentiometry. For the more weakly-binding mononegative systems, NMR shifts can provide complementary information. For these studies we use the large size-excluded tosylate anion as the supporting electrolyte and all log K values are thus relative to this notional standard [19],... 

Two further syntheses of rose oxide (415) are described. The first is a modification of the route from citronellol (416), anodic oxidation of which (in acetonitrile with tetraethylammonium tosylate as supporting electrolyte) leads to a 71 29 mixture of ns tra s-(415). The other route is of the dihydropyran type ... 

Here, we consider electropolymerized 3,4-ethylenedioxythiophene (EDT), prepared with different supporting electrolytes (see [135]) polystyrenesulfonic add (PSS), p-toluenesulfonic acid (Tos), and tetrabutylammonium perchlorate (BU4NCIO4). The anion produced from the dissociation of toluene-sulfonic acid is also called tosylate (< -SO i). Additionally, we address chemically prepared PEDOT-PSS, in a water emulsion, sodium free (<0.5 ppm), provided by Agfa Gevaert N.V. None of these blends contains PSS -Na" ", as was the case for Baytron P discussed above. The conductivity values a obtained for the polymers are summarized in Table 21.1. PEDOT/Tos is the most conductive (450 S cm ). The polyanion-based materials give lower conductivities 80 S cm for electropolymerized PEDOT-PSS and 0.03 S cm for chemically polymerized PEDOT-PSS. 

The ability of the supporting electrolyte anion to stabilize the intermediate carbo-cations in only moderately polar solvents such as CH2CI2 or THF may play an important role for product formation. The 0104 ion is known to stabilize car-bocations in ether [9] and in alcoholic solutions [10], whereas the tosylate anion (TsO ) has been suggested to add to reactive carbocations [11] (see Sect. 14.3.1). Itis unfortunate that in many cases Cl04 has proven to be superior in EGA-catalyzed reactions, since the known safety risks of organic perchlorates (explosive) prevent the general use of metal perchlorates as the supporting electrolyte. 

An important role is also played by the nature of the support electrolyte and, in particular, of the anion. As an example, tosylate greatly favors the electrodeposition of PP but is detrimental for PT for the latter, innocent anions, such as perchlorate, tetrafluoroborate, or hexafluorophosphate, are the best choice. 

The t)q)e of supporting electrolyte, and particularly the anion in the case of anodic coupling, is most important. To give an example, tosylate is very helpful for the electrodepositions of polypyrroles (see Section 4.2.3.1) but detrimental to the polymerization of polythiophenes. For the latter the anion must be an innocent type such as perchlorate, tetrafluoborate or hexafluophosphate (see Section 4.2.2.1). 

Hepten-2-one electrolyzed at a cathode potential of - 2.7 v. in dioxane-methanol containing tetraethylammonium tosylate as supporting electrolyte with carbon rod electrodes and ceramic cylinder as cathode-anode diamber divider 1,2-di-methylcyclopentanol. Y 66%. F. e. s. T. Shono and M. Mitani, Am. Soc. 93, 5284 (1971) stereochemistry of electrochemical reductions, review, cf. A. J. Fry, Topics Curr. Chem. 34, 1 (1972). 

A soln. of phenylcyclopropane and tetraethylammonium tosylate as supporting electrolyte in methanol electrolyzed at room temp, with 2 carbon electrodes at 0.08 A/cm2 and 18-40 v. until 2.4 F/mole have passed l-phenyl-l,3-dimethoxy-propane. Y 74%. F. e. s. T. Shono and Y. Matsumura, J. Org. Chem. 35, 4157 (1970). 

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