Considerable difference was observed in the reactions of B-methylstyrene (I) in nonexchanging solvents in the presence of dispersed sodium or potassium. At 100-155", in the presence of sodium, I underwent mainly dimerization to 1, 5-diphenyl-4methyl-l-pentene (V, yield 8 (r87%), whereas the fastest reaction in the presence of the more electropositive potassium was hydrodimerization resulting in 1, 4-diphenyl-2, 3-dimethylbutane (IV, ...