The synthesis of α‐tert‐butyl‐ω‐[p‐vinylphenyl]‐terminated poly(2‐methylpropene) macromonomers

In this communication a novel synthetic route to α‐ tert ‐butyl‐ω‐[ p ‐vinylphenyl]xy1terminated poly(2‐methylpropene) (PIB) macromonomers ( P3 (VB); P5 ) is described: magnified image and magnified image Attempts to synthesize such macromonomers in both one‐ and two‐step syntheses are described. The one‐step method using 4‐chloromethylstyrene/AlR3 as initiating system for the polymerization of 2‐methylpropene did not yield linear macromonomers but rather highly branched products. The alternative two‐step synthesis using 1‐(2‐bromoethyl)‐4‐chloromethylbenzene (BCB) or BCB/AgSbF, as initiator also failed to yield the desired products. Successful syntheticroutes, optimised on the basis of model experiments with low molar mass compounds, are also described for preparing the above macromonomers. Both of these routes involve isopropenylterminated PIB, which is easily assessible by Inifer technique followed by dehydrohalogenation. Friedel‐Crafts alkylation of phenol by the terminal olefin group of PIB, followed by subsequentesterification of the phenolic end‐groups with 4‐vinylbenzoyl chloride, affords the macromonomer P3(VB). Conversion of the terminal olefin group of PIB into a primary alcohol using 9‐bora[3,3, I]‐bicyclononane/H202, followed by esterification, yields the macromonomer P5 .