Anionic difunctionalization with 1,1‐bis(4‐ t ‐butyldimethylsiloxyphenyl) ethylene. Synthesis of ω,ω‐bis(phenol)‐functionalized polystyrene condensation macromonomers

Abstract ω,ω‐Diphenolpolystyrenes (6) can be synthesized in quantitative yields by reacting poly(styryl)lithium with 1,1‐bis(4‐ t ‐butyldimethylsiloxyphenyl)ethylene (1), followed by methanol termination and hydrolysis with dilute acid. The initially formed 1,1‐bis(4‐ t ‐butyldimethylsiloxyphenyl)alkyllithium can be reacted with additional styrene monomer to form a polystyrene internally substituted with two in‐chain phenol groups after methanol termination and acid hydrolysis. The diphenol‐substituted polystyrene condensation macromonomers have been characterized by end‐group titration, size exclusion chromatography, thin‐layer chromatography, and ultraviolet‐visible, 1 H and 13 C NMR spectroscopy. Chain‐extension reactions of 6 ( M n = 2.6 × 10 3 g mol −1 ) with bis(trichloromethyl)carbonate produced the corresponding comb‐type, branched polymer with estimated M n (SEC, polystyrene standards) = 1.2 × 10 4 g mol −1 and no detectable residual condensation macromonomer. The second order rate constants for the addition reaction of excess poly(styryl)lithium with 1 and with 1‐(4‐ t ‐butyldimethylsiloxy‐phenyl)‐1‐phenylethylene (3) have been estimated to be 1.7 × 10 −3 M −1/2 S −1 and 3.2 × 10 −3 M −1/2 S −1 respectively. A sigma value (σ) of −0.46 has been estimated for the t ‐butyldimethylsiloxy substituent.