Organoboron polymers, reactions

Hydroboration of a,C0-dienes with monoalkylboranes gives reactive organoboron polymers which can be transformed into polymeric alcohols or polyketones by carbonylation, cyanidation, or the DOME reaction followed by oxidation (446—448). 

IV Facile Preparation of Organoboron Polymer Electrolytes via Dehydrocoupling Reaction of 9-Borabicyclo[3.3.1]nonane... 

Figure 7 Some 77-conjugated fluorescent organoboron polymers (7) synthesized by the hydroboration polymerization reaction. (Adapted from ref. 27.)...

B. Reactions of Organoboron Polymers Prepared by Hydroboration Polymerization... 

To synthesize the poly(ketone)s selectively, the reaction between the organoboron polymers and KCN was reported (scheme 6).8 After oxidation of the reaction mixture, followed by coagulation, the desired poly(ketone)s were obtained. The yielded polymers... 

The preparation of a functional segmented block copolymer was also investigated (scheme ll).15 First hydroboration polymerization of the oligomer using thexylborane was carried out. Then the obtained organoboron polymer was subjected to a chain-transformation reaction (DCME rearrangement). DCME and lithium alkoxide of 3-ethyl-3-pentanol in hexane was added to a THF solution of the polymer at 0°C. 

IV. FACILE PREPARATION OF ORGANOBORON POLYMER ELECTROLYTES VIA DEHYDROCOUPLING REACTION OF 9-BORABICYCLO[3.3.1JNONANE AND... 

To immobilize such anions as borate, organoboron polymers were reacted with aryllithium reagents.31,32 The reaction of alkylborane polymers with n-BuLi was examined first however, the ionic conductivity of the resulting material was very low. Moreover, complicated peaks were observed in the H-NMR spectrum. Conversely, selective lithium borate formation was observed in the nB-NMR spectrum when PhLi was employed (scheme 6). An ionic conductivity of 9.45 X 10 7Scm 1 was observed at 50°C. The observed ionic conductivity was relatively low because of the decreased number of carrier ions compared with dissolved salt systems. However, the lithium transference number of this polymer was markedly high (0.82 at 30°C). 

Reactions of organoboron polymer electrolytes with aryllithium reagents suffered low conversion due to relatively low reactivity of the mesitylborane unit. Moreover, incorporation of aryl substituent in side chains resulted in higher glass-polymer electrolyte-transition temperatures. 

A synthesis of comblike organoboron polymer/boron stabilized imidoanion hybrids was examined via reactions of poly(organoboron halides) with 1-hexylamine and oligo(ethylene oxide) monomethyl ether and subsequent neutralization with lithium hydride (scheme 8). The obtained polymers (10) were amorphous soft solids soluble in common organic solvents such as methanol, THF, and chloroform. In the nB-NMR spectra (Fig. 11), neutralization of the iminoborane unit with lithium hydride... 

Qin, Y., Cheng, G., Achara, O., Parab, K., and Jakle, F. (2004) A new route to organoboron polymers via highly selective polymer modification reactions. Macromolecules, 37, 7123-7131. 

Scheme 2 demonstrates the versatile reactions of organoboron polymers prepared by hydroboration polymerization. For example, the polymer prepared from thexylborane and 1,7-octadiene was reacted with carbon monoxide at 120°C followed by treatment with NaOH and H2O2 to produce a poly alcohol [7]. This conversion includes the migrations of polymer chain and thexyl group from boron atom to carbon as shown in Scheme 3. When this reaction was carried out under milder condition,...

For the selective preparation of polyketone, the organoboron polymer prepared by hydroboration polymerization between thexylborane and 1,7-octadiene was subjected to reaction with KCN [8]. After oxidation of the reaction mixture followed by coagulation, the desired polyketone was obtained selectively. The polymer formed was a... 

Hydroboration of terminal diyne gives organoboron polymer having branched structure due to the further hydroboration reaction toward the initially formed vinylborane structures. That is, terminal diynes are taken to have a potential as a multifunctional monomer. When the polymerization between 1,7-octadiene and thexylborane was carried out in the presence of a small amount of 1,7-octadiyne, the molecular weights of organoboron polymers were found to be increased when the ratio of diyne/diene was increased [5]. 

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