Polyhomologation: the living polymerization of ylides

The polymerization of dimethylsufoxonium methylide to produce linear polymethylene polymers is described. The reaction is catalyzed/initiated by trialkylboranes and gives organoboron star polymers as the primary product. The reaction is a living polymerization, providing control over molecular weight and functionality at the polymer chain ends. A variety of novel polymethylene architectures are available by this methodology.