Tetrabutylammonium fluoroborate

The reduction of aroyl chlorides take a different course in the presence of Ni(ll) salts. Reaction is best effected in an undivided cell with a nickel anode and a nickel foam cathode with acetonitrile containir tetrabutylammonium fluoroborate as electrolyte. Symmetrical ketones are formed [173], Substimted benzoyl chlorides yield the benzophenone in 47-72% yields. Phenacetylchloride also gives the ketone in good yield but in general, alkanoyl chlorides do not react. 

Cyclohexenone is reduced either by sodium amalgam [138] or electrochemically in acetonitrile containing tetrabutylammonium fluoroborate [139] and affords mainly the tail-to-tail diketonic hydrodimer. Some 10-26% of the head-to-tail hydrodimer has been detected in the mixture of products from reduction at a mercury cathode in aqueous ethanol under both acidic and basic conditions [140]. Substituents on the 3- and 4-positions, as in XXXIII, cause formation of some head-to-tail XXXV and head-to-head hydrodimers XXXVI (see Table 9). The product ratios depended on the concentration of water in acetonitrile used as solvent. Other work discussed later indicates that the presence of metal ions that can coordinate with alkoxy groups also changes these product ratios. 

Table 1. Cyclic voltammetry of the diphenyl ftilleroids Ph C i to Ph,2Ce. Experimental conditions Pt woridng and counterelectrodes Ag/AgCl/3M NaCl, reference electrode Ferrocene internal reference (+620 mV) 0.1 M TBABF4 (tetrabutylammonium fluoroborate) in THF (tetrahydrofiiran) in a dry box.

Acetonitrile solvent, 0.1 N tetrabutylammonium fluoroborate as electrolyte, glassy carbon electrode used as working electrode. 

The conjugated polymeric liquid crystal, poly(bis(4-methoxy-4 -hexyloxybiphenyl)dipropargylmalonate) (PMHBDPM), can be reversively doped by using electrochemical doping with the common three-electrode method utilizing acetonitrile solution containing tetrabutylammonium fluoroborate (TBAFB) as an electrolyte. 

Anodic oxidation of BusSn-protected unsaturated hemi-3-acetal (27) with tetrabutylammonium fluoroborate, as the supporting electrolite <92JA7594>, gave huorinated oxepan (28) (61%) and its dehydrofluorination product (29) (28%). 

A soln. of 3,3, 4,4 -tetramethoxybibenzyl and trifluoroacetic acid in methylene diloride containing tetrabutylammonium fluoroborate electrolyzed under Ng with stirring at 8° with Pt-electrodes in a closed 2-compartment cell divided by a glass fritt until 4F/mol have passed through 2,3,6,7-tetramethoxyphenanthrene. Y almost 100%. F. e. s. A. Ronlan, O. Hammerich, and V. D. Parker, Am. Soc. 95, 7132 (1973) also cyclodimerization s. J. Org. Chem. 39, 1014 (1974). 

Fig. 6.7 Effect of scan rate on cyclic voltammograms at permanently heated wire electrodes. CVs of reversible redox couples at different scan rates [(a) 20 V/s (b) 1 V/s (c) 100 mV/s]. Left-. [Ru (NHs) ] (1 mmolA) in aqueous KCl solution (0.1 molA) at a Pt wire 0.25 pm in diameter, reference electrode SCE, temperature 49 °C. Right Ferrocene (2 mmol/l) in DMF with suppmting electrolyte tetrabutylammonium fluoroborate (NBU4BF4) 0.5 mol/l, temperature 56 °C, reftaence electrode Ag/0.01 MAg /0.1 M NBu4BF4/MeCN/A).l M NBu4BF4/DMF. From [14], with permission...

Experiments were carried out in DMF with 4 mM AC, and PhOH at concentrations in the range 0.1-0.43 M, with tetrabutylammonium tetra-fluoroborate as a supporting electrolyte. Distances were established using the positive feedback response for the oxidation of decamethylferrocene, which was added to solutions at mM levels. A 7 /xm diameter C fiber UME was employed as the tip, while the substrate was a 60 p,m diameter Au disk electrode. Typical steady-state tip and substrate approach curves for the diffusion-limited reduction of AC at the tip and the oxidation of AC - at the substrate are shown in Fig. 28. At a qualitative level, the tip current shows the features predicted for ECE/D1SP1 processes, identified in Sec. IV.A, while the substrate current—always of opposite sign to the tip current— points unambiguously to a D1SP1 pathway. 

An erroneous 2e mechanism has been presented by Lund. For less easily oxidizable hydrocarbons acetonitrile with tetrabutylammonium tetra-fluoroborate as supporting electrolyte is used. 

Pyridines containing leaving groups (Hal, SO2R, NO2) in position 2 are often used as starting materials for preparation of 2-fluoropyridines in nucleophilic substitution reactions. Typical nucleophiles are fluorides of alkaline metals, hydrofluoric acid, tetrabutylammonium fluoride, and fluoroboric acid. Although this... 

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