Direct electrochemical reduction of a bromo-propargyloxy ester at vitreous carbon cathodes in dimethylformamide

Organic cyclisations of propargyl and allyl bromoesters in microemulsions catalysed by electrogenerated nickel(I) tetramethylcyclam

“…1, curve B, direct reduction of a 1.7 mM solution of the bromoester, 1a, at a glassy carbon electrode in MTAB/tetradecane/water/1-pentanol microemulsion at a 0.10 V s À1 gives a first irreversible peak at a potential approximately À1.42 V followed by a second irreversible peak at À1.71 V. Peak potentials for the first irreversible reduction of 1a in other microemulsions were in the range À1.42 to À1.54 V. Cyclic voltammograms for 2 mM of 1b and 1c at a glassy carbon electrode in different microemulsions, also showed a similar behaviour. For compound 1b in MTAB lE, the first voltammetric peak was at À1.50 V followed by a second irreversible peak at À1.69 V, whereas for compound 1c the corresponding first peak potential is À1.45 V followed by a second irreversible peak at À1.70 V. On the basis of our previous paper [29] where we have provided a detailed analysis of the cyclic voltammograms for the direct reduction of ethyl 2-bromo-3-(3 0 ,4 0 -dimethoxyphenyl)-3-(propargyloxy)propanoate (1a), we attribute the first peak to the irreversible two-electron reductive cleavage of the carbon-bromine bond.…”

Electrochemical hydrogenation of α-ketoesters and benzoxazinones using carbon electrodes and a sustainable Brønsted acid

“…15 Their application in direct, electrochemical modifications of organic materials has been comparatively limited. [16][17][18][19][20][21] Here, we report that unsaturated a-ketoester and benzoxazinone substrates can be selectively hydrogenated at carbon electrodes using sustainable Brønsted acids such as acetic acid (Figure 1).…”

Recent advances in the electrochemical construction of heterocycles

“…Such ring-closing reactions are frequently carried out using toxic tri- n -butyltin hydride in combination with a radical initiator such as AIBN. Peters and co-workers described an electrochemical alternative using cathodically generated nickel(I) complexes as mediators [41–42]. Under potentiostatic conditions (C.P.E.…”

“…= controlled potential electrolysis) in a divided cell, bromopropargyloxy ester 12 was converted using [Ni(tmc)]Br 2 (tmc = 1,4,8,11-tetramethylcyclam) as catalyst, leading to cyclization products 13 and 14 (Scheme 5). When 12 was electrolyzed in absence of mediator, significantly lower yields were obtained [42]. …”