Formation of Grignard reagents from 3-bromo-NN-dimethylbenzylamine and 4-bromo-NN-diethylbenzylamine and their reactions with benzaldehyde

3-Bromo-NN-dimethylbenzylamine and 4-bromo-NN-diethylbenzylamine failed to react with magnesium in ether in accordance with reports in the literature for similar compounds, but the Grignard reagents were easily obtained using tetrahydrofuran as the solvent. Reaction with benzaldehyde produced the expected alcohols; and, unexpectedly, the corresponding ketones were also obtained. By appropriate modification of the experimental procedure, either alcohol or ketone could be obtained exclusively.