Enecarbamates anodic oxidation

The anodic oxidation of carbamates of pyrrolidine and piperidine in a nucleophilic solvent such as acetic acid or methanol yields a,/ -disubstituted compounds in which the nature of the a- and -substituents depends on the reaction conditions employed (equation 9)10. This a,/ -disubstitution has been explained by the intermediary formation of the enecarbamate and its further anodic oxidation. 

Indeed, the anodic oxidation of enecarbamates in acetic acid in the presence of potassium or sodium acetate yields the corresponding a,/ -diacetoxycarbamates in reasonable yields (equation 10). 

When ammonium chloride is used as the supporting electrolyte in the anodic oxidation of enecarbamates in acetonitrile or methanol, chlorination at the -position takes place. In the mechanism of this -chlorination, the electron transfer from the unsaturated bond of the enecarbamate may not be involved, but the chloride ion is anodically oxidized to a positively charged active species which subsequently adds to the -position of the... 

Generally, enamines, enamino esters and ketones, enamides and enecarbamates can give the following products after anodic oxidation (Scheme 7) ... 

Addition to the double bond of enecarbamates is observed during anodic oxidation in methanol in presence of an ammonium halide, leading to the product of halomethox-ylation [Eq. (28)] [155]. The enecarbamates are available through electrochemical a-meth-oxylation of the carbamate followed by methanol elimination (see Sec. VIII.B). 

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