Photochemical Reactions of Methyl Iodide with Aromatic Compounds

Article abstract of DOI:10.1021/jo00339a004

The photolysis of methyl iodide in an excess of aromatic compounds (ArH) gave the ring-methylated aromatics in rather high yields (40-70percent) but no side-chain-methylated compounds.The observed orientation was abnormal, i.e., o/2 ca. m/2 ca. p, compared with that in ordinary Me radical substitutions (o/2 > p > m/2), especially with alkylbenzenes, where 2 is the statistical factor.The effect of wavelength on the yield of iodine was also observed, i.e., a higher yield of I2 at 254 nm and a lower yield of I2 and a higher yield of HI and ArI at > 290 nm.Both the addition of I2 to the reaction system and the removal of the formed I2 by Na2S2O3 brought about no effect on the orientation.These results along with the effect of solvents and no influence of oxygen as a radical scavenger suggest a mechanism via a complex between methyl iodide and the aromatics which is different from a direct radical attack.