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

Abstract

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.