Electro-organic chemistry. Part 93. Electro-organic transformation of aldehydes and ketones to α-hydroxylated acetals utilizing mediators and some synthetic uses of the products

Electro-oxidation of aldehydes (R1R2CHCHO) and ketones (R1R2HCOR3) in methanol containing iodide ion (I–) and KOH gave the corresponding α-hydroxylated acetals [R1R2C(OH)CH(OMe)2 and R1R2C(OH)C(OMe)2R3, respectively] in good yields. The first step of this oxidation is explained in terms of the attack of an anodically generated active iodine species ‘I+’ on enols of R1R2CHCHO and R1R2CHCOR3. α-Hydroxy acetals were useful starting materials as exemplified by reaction with aniline or methyl carbamates in the presence of Lewis acids to afford β-keto amine derivatives. The anodic oxidation of α-hydroxy acetals was also carried out.