Dimethylsulfoxonium methylide living polymerization

The polymerization of dimethylsulfoxonium methylide (17) initiated by trialkylborane, which Shea et al. developed, is classified as the first category. Propagation involves insertion of 17 into the terminal C-B bond with elimination of DMSO. The polymerization was carried out in toluene at 70-80 °C, followed by oxidative workup to yield hydroxyl-terminated polymethylene (Scheme 71). The Mn values were very close to the calculated values from the feed ratio of 17 to trialkylborane, and the Mw/Mn ratio ranged from 1.04 to 1.17. These results are consistent with the character of living polymerization. 

Our research has focused on polymerization reactions that employ nonolefin monomers, more specifically the polymerization of yhdes and diazoalkanes. The carbon backbone is built one carbon at a time (Cl polymerization). These studies draw upon earlier investigations of the Lewis-acid-catalyzed polymerization of diazoalkanes (Imoto and Nakaya, 1972 Maria and Bernhard, 1974 Bawn et al, 1959) and build upon our discovery of the trialky Iborane-initiated living polymerization of dimethylsulfoxonium methylide 1 (Shea et al., 1997). 

Table 11.1 Experimental degrees of polymerization (DPexpt.) and polydispersities of ot-hydroxy-

Shea, K.J., Busch, B.B., and Paz, M.M. (1998a) Polyhomologation Synthesis of novel polymethylene architectures by a living polymerization of dimethylsulfoxonium methylide. Angewandte Chemie-International Edition, 37,1391-1393. 

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