Difunctional anionic polymerization initiators from the reaction of butyllithium with trans‐stilbene

The reaction between butyllithium and trans‐stilbene in benzene solvent yields a mixture of 1,2‐diphenylhexyllithium and 1,2,3,4‐tetraphenyloctyllithium. These compounds readily disproportionate to 1,2‐diphenylhexane, 1,2,3,4‐tetraphenyloctane, 1,2‐dilithio‐1,2‐diphenylhexane, and 1,2‐dilithio‐1,2,3,4‐tetraphenyloctane. The dilithio compounds are efficient initiators for the anionic polymerization of styrene, yielding polymers with predictable molecular weights and narrow molecular weight distributions, (M̄w/M̄n ≈ 1.1).