Oxidation of diethyl (pyridylmethyl)malonates with manganese(III) acetate, cerium(IV) ammonium nitrate, and iron(III) perchlorate in the presence of alkenes and alkynes

The oxidn. of substituted di-Et 2-, 3-, or 4-picolylmalonates by Mn(OAc)3 in HOAc, Ce(NH4)2(NO3)6 in MeOH or HOAc, and Fe(ClO4)3 in MeCN in the presence of substituted alkenes and alkynes affords substituted tetra- or dihydroquinolines and/or isoquinolines in good to excellent yield. Thus, 2-picolylmalonate I and CH2:CH(CH2)5Me upon treatment with Mn(OAc)3 in HOAc afforded 90% quinoline II. 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 addn. to olefins, and intramol. homolytic substitution to protonated or metal-complexed heteroarom. bases by the resulting substituted C radicals is suggested