Nucleophilic substitutions initiated by electrochemical oxidation. I. Intramolecular nucleophilic substitutions

Abstract

Reaction of (S)-(+ )-l-Ferrocenylethanol (8) with Acetic Acid in Benzene.-A solution of glacial HOAc (6 g, 0.1 mol) and (S)-( + )-8 [4.6 g, 0.02 mol, [a]26d +29.3°(c 1.7, benzene)] in 130 ml of dry benzene is refluxed for 4 hr while water separates (Dean-Stark trap). The solvent is removed in vacuo and the crude acetate (9) (4.9 g, 90%) is purified by chromatography (activated alumina, 3.5 X 20 cm, MCB, 80-325 mesh, eluent-Skelly B). The resulting yellow solid is sublimed: 35" (1 Torr), [<x]26d 0 (ethanol).

Stepwise Oxidative C–C Coupling and/or C–N Fusion of Zn(II) meso-Pyridin-2-ylthio-porphyrins

“…After nucleophilic attack of the pyridine substituent on the oxidized naphthol fragment, a new 5-membered ring was formed and the pyridinium cation was obtained in low yield. 38 The second example was published in 2015 by Yoshida's group. 39 In this report, an electrochemical intramolecular C−N coupling between the phenyl moiety and thio-or hydroxypyrimidine substituents was achieved in high yield affording new five-membered rings.…”

Oxidative C–N fusion of pyridinyl-substituted porphyrins

“…The first one described the electrochemical oxidative C-N fusion of a naphthol-substituted pyridine but the yield was only 4%. 18 In the second example the electrochemically generated C-N benzene-based fused compounds were non-isolated intermediates. 19 To our best knowledge, no example of C-N fused porphyrin synthesized by the direct intramolecular oxidative C-N fusion of a peripheral heterocyclic imine with a meso and/or b carbon from the porphyrin core is reported.…”

Regioselective Pyridination of m-Benziporphyrin

“…Alternatively, the formation of 2 may be viewed as N-arylation of pyridine, which produces a phenylpyridinium salt. Such reactions normally require highly activated aryl halides as substrates or are performed using electrochemical oxidation …”