Optional ortho or alpha hydroxymethylation of alkylarenes

Article abstract of DOI:10.1016/0022-328X(91)83276-A

Treatment of arenes carrying methyl or primary alkyl groups in tetrahydrofuran solution with potassium tert-butoxide activated butyllithium followed by reaction with formaldehyde gives 2-arylalkanols.In contrast, if prior to the addition of the electrophile a stoichiometric amount of magnesium dibromide is added then the regioisomeric 2-alkylbenzyl alcohols are formed.