Oxidation of Diethyl (Pyridylmethyl)malonates with Mn(III) Acetate, Ce(IV) Ammonium Nitrate, and Iron(III) Perchlorate in the Presence of Alkenes and Alkynes

Article abstract of DOI:10.1021/jo00018a024

The oxidation of substituted diethyl 2-,3-, or 4-picolylmalonates (1a-g) by Mn(III) acetate in acetic acid, Ce(IV) ammonium nitrate in methanol, and Fe(III) perchlorate in acetonitrile in the presence of substituted alkenes (2) and alkynes (3) affords substituted tetra- or dihydroquinolines and/or isoquinolines (4-9) in good to excellent yield.The influence of reaction medium on yield and isomer distribution has been investigated.A mechanism involving oxidative deprotonation of malonic esters by high-valent metal salts to malonyl radicals, their addition to olefins, and intramolecular homolytic substitution to protonated or metal-complexed heteroaromatic bases by the resulting substituted carbon radicals is suggested.