Organoboron main-chain polymers

Hydroboration polymerization between diene monomers and 2,4,6-trimethylphenylborane (mesitylborane)6 or 2,4,6-triisopropylphenylborane (tripyl-borane)7 gave organoboron main-chain polymers (scheme 3). The polymerization was... 

In one of their notable examples, the hydroboration polymerization of low molecular weight allyl-telechelic polyisobutylene with tripylborane (trip = 2,4,6-triisopropylphenyl) was found to yield air-stable organoboron segmented block copolymers. These boron main-chain polymers (8) (Fig. 8), unlike the general ones, were stable to air. The stability was due to the steric hindrance of the bulky tripyl groups preventing oxygen attack of the borons.28... 

FULLY AROMATIC ORGANOBORON POLYMERS BEARING MONOMERIC IMINOBORANE IN THEIR MAIN CHAIN 8>... 

Some procedures to prepare main-chain polymeric boron Lewis acids have been also developed. The most commonly used method for the synthesis of main-chain organoboron polymers is the hydroboration polymerization developed by Chujo [29, 30]. For example, hydroboration between (47) and (48) in TH F gave the organoboron... 

Nagata, Y Chujo, Y. 2008. Synthesis of methyl-substituted main-chain-type organoboron quinolate polymers and their emission color tuning. Macromolecules 41 2809-13. 

The organoboron polymers prepared by hydroboration polymerization have a new structure consisting of C-B bonds in the main chain. Generally, these organoboron polymers can be regarded as a polymer homologue of trialkylborane, which is known to be a very versatile compound in organic synthesis [6]. In other words, the obtained polymers by hydroboration polymerization can be expected as a novel type of reactive polymers. 

Recently, we explored a novel polyaddition between dienes and monoalkylboranes and termed this hydroboration polymerization (18). Diynes and dicyano compounds can also be used in this hydroboration polymerization. The organoboron polymers obtained are effectively converted to polyalcohols or polyketones. In other words, polymers having organoboron units in the main chains can be expected to be reactive polymers. Here, the scope of these hydroboration polymerizations is viewed as methodologies for the preparation of organoboron polymers. 

For the selective preparation of polyketones, the organoboron polymer prepared by hydroboration polymerization between thexylborane and 1,7-octadiene was subjected to reaction with KCN (22). After oxidation of the reaction mixture, the desired polyketone was obtained. The polymer formed was a white solid and stable in air. This reaction also includes the migration of main chains of organoboron polymer from boron to carbon. 

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