Optional ortho or Alpha Hydroxymethylation of Alkylarenes.

Treatment of arenes carrying Me or primary alkyl groups, e.g., EtPh, in THF with potassium tert-butoxide activated butyllithium followed by reaction with formaldehyde gives 2-arylalkanols, e.g., PhCHMeCH2OH. In contrast, if prior to the addn. of the electrophile a stoichiometric amt. of magnesium dibromide is added then the regioisomeric 2-alkylbenzyl alcs., e.g., 2-EtC6H4CH2OH, are formed. [on SciFinder (R)]