Electrochemical addition

In an anodic addition reaction two molecules of a nucleophile are added across a double bond (Eq. (8) ) with loss of two electrons to the anode. This provides an attractive and important route to 

Cathodic addition reactions are of great preparative value, since the general scheme (9) of course accommodates the synthetically important reduction of unsaturated compounds  

As industrial important anodic addition reaction can be mentioned the synthesis of chiral 1,2-diols by indirect electrolysis. This reaction can be carried out, using a double mediator system consisting of ferricyanide and osmium tetroxide in the presence of chiral ligands. As an alternative to ferricyanide, electrogenerated iodine may be used. This reaction can be seen as an electrochemical variant of the asymmetric bishydroxylation introduced by Sharpless (Fig. 9-5). 

The dimethoxylation of furan and fiiran derivatives using bromide redox catalyst gives 2,5-dimethoxy-2,5-dihydrofurans which can serve as interesting synthetic intermediates (Eq. 9-27)  

This process is commercialized by BASF for the formation of succinic dialdehyde and by Otsuka, Japan, for the synthesis of maltol and ethyl maltol. 

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Electrochemical addition of perfluorobutyl iodide to 2-methyl-3-butyn-2-ol followed by basic dehydroiodmation and thermal cleavage gives perfluorobutyl-acetylene in an overall yield of 83% [34] (equation 26)... 

Conjugate additions. Cobalt bromide catalyzes electrochemical addition of aryl halides to activated alkenes. 

Mukhopadhyay B, Sundquist J, Schmitz RJ. (2007). Removal of Cr(VI) from Cr-contaminated groundwater through electrochemical addition of Fe(II). Journal of Environmental Management 82(l) 66-76. 

Electrochemical addition of carboanions of nitrocompounds to levoglucosenone, a compound with a chiral carbohydrate skeleton L — Laikhter (1993)... 

A catalyst for the selective cyclodimerization of butadiene to 4-vinylcyclo-hexene can be generated by the reduction of [Fe(NO)2Cl], with metal carbonyls or electrochemically. Addition of cyclic amines to the isoprene dimerization catalyst [NiCl2(PPhs)2]-NaBH4-H20 enhances the formation of cyclic dimers the product distribution has been correlated with an electronic and structural properties of the amine. [Ni P(n-OC6H4R)3 J (R = Ph or SiMes) catalyses the selective (95 %) dimerization of butadirae to cyclo-octa-1,5-diene the catalysts appear to operate via two active centres, probably the Ni and P atoms. When solutions of (44) are allowed to stand and then treated with HCl or Brj signficant amounts of [1,1,3,3- H4]- and [2,2,3,3- H4]-butane are produced in addition to the anticipated [1,1,4,4- H4]-isomer. This would seem to indicate that there is an equilibrium (14) and in keeping with this (44)... 

Terminal acetylenes can be alkylated to give chain-lengthened internal acetylenes in good yield, either by the rapid addition of trialkylalanes in the presence of nickel(ii) catalysts or by electrochemical addition of organoboranes. Hydroalumination may be used in a convenient conversion of terminal olefins into the corresponding acetylenes. An improved procedure for the synthesis of cyclo-octyne from cyclo-octene by a bromination-dehydrobromination sequence has been reported. ... 

Electrochemical Addition of Aryl Halides onto Activated Olefins... 

As already mentioned for the electrochemical addition of aryl halides onto olefins, the use of a consumable iron is necessary for the reaction to be catalytic in... 

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