Nickel-Catalyzed Alkene Difunctionalization as a Method for Polymerization

Alkene dicarbofunctionalization isa rapidly emerging tool forcomplex molecule synthesis that installs two carbon fragments regioselectivelyacross an alkene. This method has the potential to engineer stereodefinedpolymers, yet the application of difunctionalization reactions topolymer synthesis remains unexplored. Herein, we describe the firstexample of a Ni-catalyzed difunctionalization of alkenes with arylboronicesters and aryl bromides innate to the alkene. The polymerizationreaction proceeds regioselectively with the addition of the aryl bromideto the terminal alkenyl carbon and arylboronic ester to the internalbenzylic carbon. The resultant poly[arylene-& alpha;-(aryl)ethylene]scomprise aryl groups installed at regular intervals along the polymerbackbone through chain propagation in two directions. Polymers withmolecular weights generally ranging from 30 to 175 kDa were obtainedafter successful fractionation from oligomeric species. Thermal analysisof the poly[arylene & alpha;-(aryl)ethylene]s revealed stability upto & SIM;399 & DEG;C, with a T (g) of 90 & DEG;C, both of which are similar in value to poly(styrene)s andpoly(phenylene methylene)s.