Abstract: Reactions of alkyl 2, 5-dimethoxyphenyl ketones with t-butylmagnesium chloride were shown to yield the 1, 2-adducts, 1, 6-adducts, and the corresponding alcohols as the major products.The product distributions were found largely dependent on the alkyl group of the ketone and the solvent used. The bulkier the alkyl group . the more favoured the formation of the 1.6-adduct or the alcohol. On the other hand, the formation of the 1, 6adducts became a more important pathway when the reactions were carried out in tetrahydrofuran than in ether.In addition. the trace amount of transition metals in magnesium alsoshowed a little effect on the product distribution. Based on the experimental observations, we suggested that the above reactions, initiated by a single electron transfer, would possiblyundergo via the intermediates, radical ion pairs and radical pair, and the final product distributions greatly depended on the nature of the generated intermediates in each of the reactions.

Key words: Alkyl dimethoxyphenyl ketone.Grignard reaction, Single electron transfer