Polymerization cross-coupling

With the bisoxazoline hgand (S)-Phbox and CuCl, the asymmetric oxidative couphng of 2-naphthol and hydroxy-2-naphthoates resulted in an asymmetrically substituted 2,2 -binaphthol with ee s of up to 65% [260]. On the basis of the previous results obtained with this catalyst system, the asymmetric oxidative cross-coupling polymerization of 2,3-dihydroxynaphthalene [261] and methyl 6,6 -dihydroxy-2,2 -binaphthalene-7,7 -dicarboxylate [262] as well as the copolymerization of 6,6 -dihydroxy-2,2 -binaphthalene and dihexyl 6,6 -dihydroxy-2,2 -binaphthalene-7,7 -dicarboxylate with Cu diamine catalysts were carried out imder aerobic conditions, using O2 as the oxidant, and a cross-coupling selectivity of 99% was achieved [263]. 

Cross-coupling Polymerization with Organometallic Reagents of sp -Hybridized Carbons 653... 

The cross-coupling polymerization with dihaloarenes leads to poly(phenylene-vinylene)s (PPVs), which are widely employed as conductive and electroluminescent polymers. ... 

Pu reported the synthesis of axially chiral-conjugated polymer 82 bearing a chiral binaphthyl moiety in the main chain by the cross-coupling polymerization of chiral bifunctional boronic acid 80 with dibromide 81 (Equation (39)). The polymer is soluble in common organic solvents, such as THE, benzene, toluene, pyridine, chlorobenzene, dichloromethane, chloroform, and 1,2-dichloroethane. The polymer composed of racemic 80 was also synthesized, and the difference of characteristics was examined. Optically active polymer 82 was shown to enhance fluorescence quantum yield up to = 0.8 compared with the racemic 82 ( = 0.5). Morphologies of the optically active and racemic polymers were also compared with a systematic atomic-force microscopy (AEM). 

Cross-coupling Polymerization at sp-Hybridized Carbons 11.19.3.1 Polymerization by Sonogashira-Hagihara Coupling... 

Heitz has performed the cross-coupling polymerization using two-step one-pot process. The first step is the reaction of 1,4-diiodobenzene 107 with 2 equiv. of 2-methyl-3-butyn-2-ol 108 at room temperature in the presence of an aqueous base to give the protected bisalkyne 109. Following polycondensation with another equivalent of dihaloarene 110 leads to the corresponding polymer 111 at 100°C (Equation (53)). The overall yield of 111 was 50-90% and the average molecular weight (M ) was 1400-48 200. 

PdCl2(PPh3)2, or Pd(dba)2/P(furyl)3. No further additive is necessary to activate the tin reagent and to induce the cross-coupling polymerization. In addition to the diiodoarenes with different substituents, dibromoazobenzenes and dibromosiloles (silacyclopentadiene) are also employed as the co-monomers. 

Alkynyl halides are possible monomers for the cross-coupling polymerization, in which boronic acids are used as the organometallic counterparts. For example, bifunctional boronic acid 46 is allowed to react with l,4-di(bromoethy-nyl)benzene 138 to afford the corresponding PAE 139 as shown in Equation (64). Polymerization proceeds at room temperature in toluene in the presence of silver(i) oxide as an activator of the boron reagent. The polymer 139 is obtained in 30-50% yield showing color of red-brown to deep red-brown and slight solubility in toluene (<0.1 wt.%). The molecular weight (Mr of 139 was 1700-4300 (PDI = 1.3-3.6). 

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