If employed in tetrahydrofuran, stoichiometric amounts of butyllithium and potassium tert- butoxide react with benzene under clean monometalation. In hexane suspension, however, considerable amounts of meta-and para-disubstituted by-products are obtained (approx 10%). They become preponderant if a three-fold excess of the metalating agent is used. Naphthalene leads under the same conditions to a mixture of two mono-and ten di- ...
