Mechanism of arylation

There has been relatively little work on the mechanism of arylation of heterocyclic compounds, but the arylation of homocyclic compounds has been studied in great detail. Those mechanistic aspects of the reactions with heterocycles which have been examined parallel closely the corresponding aspects of the reactions of homocycles, and there is... 

Figure 3.15 Mechanism of aryl ether cleavage during alkaline pulping.

K.H. Pawlowski and B. Schartel, Flame retardancy mechanisms of aryl phosphates incombination with boehmite in bisphenol A polycarbonate/acrylonitrile butadiene styrene blends, Polym. Degrad. Stabil., 2008, 93 657-667. 

Martin et al report investigations on the kinetics and the mechanism of aryl cyanate formation frx>m cyanogen bromide and phenols in the presence of different tertiary aliphatic amines. According to Vo-winkel," the use of diethyl ether as the solvent at -10 C raises the yields and various patents describe how the amines can be replaced by sodium hydroxide. There are even reports on work in aqueous solution under phase transfer conditions. With all synthetic variants it is crucial to avoid a surplus of the phenolate as only under these conditions can the often quite fast formation of imino carbonates be prevented (equation 28). 

Scheme 4.42 Ligand coupling mechanism of arylation reactions with aryllead triacetates...

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