CHEMISTRY OF ARYLALKYL RADICAL CATIONS - DEPROTONATION VS NUCLEOPHILIC-ATTACK

Radical-cation-mediated oxidation of 9-methylanthracene (9MA) by pyrid ine/iodine in chloroform produces mainly the product of nucleophilic a ttack at the open C-10 position. When methyl is replaced by ethyl as i n 9-ethylanthracene (9EA), the nucleophilic product is the only one ob served. Alternatively, aceanthrene (AA), the 1,9-ethano-bridged equiva lent of 9EA, produces mainly the product of side-chain substitution. S tereoelectronic control in the deprotonation is proposed as the ration ale for this difference in reactivity, as well as for other radical-ca tion-mediated oxidations.