Step-Growth Electrophilic Oligomerization and Polymerization Reactions

Step-Growth Electrophilic Oligomerization and Polymerization Reactions 

VIRGIL PERCEC and DALE H. HILL Case Western Reserve University, Cleveland, Ohio 

BENZYUC CARBENIUM IONS AS PROPAGATING SPECIES A. Linear Poly(vinylbenzene) 

The CF3S03H-initiated polymerization of DVB proceeds in a similar manner with the stepwise dimerization resulting in a product with a, -vinyl groups that can participate in further reactions [Eq. (1)] [3]. 

The structure of the product formed is determined by the reaction conditions and by the structure of the divinylbenzene substrate. Where the DVB has one a-alkyl substituent present, the benzylic carbenium ion that is formed after dimerization is further stabilized by two alkyl groups. As a result of this added stabilization the elimination reaction is slowed and the carbenium ion is long lived enough to participate in an internal Friedel-Crafts alkylation reaction. Thus the indane structure is favored to a greater extent [8]. 

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