Arylether synthesis

Jurs, J.L. Tour, J.M. Novel flame retardant poly-arylethers synthesis and testing. Polymer 2003, 44. 

With alcohols or more often with alcoholates (refs. 51 - 56) or phenolates (refs. 57 - 64) the arylethers are formed. Typically, one of the Ullmann reactions is corresponding to the diarylethers synthesis. 

Figure 6. Convergent synthesis of poly(arylether) dendrimers by Frechet et al.

The most convenient method of preparing the flexible (low Tg) system is to employ the Ullmann ether reaction of dibromobenzene and aromatic bis-diols followed by catalytic replacement of the bromine atoms by terminal acetylene groups. A host of commercially available bis-diols have been used in the synthesis with both meta and para dibromobenzene. Low Tg arylether oligomers have been prepared containing sulfone, sulfide, carbonyl, isopropyl and perfluoroisopropyl groups in the backbone (9). 

The Ullmann coupling is the classical example of Cu-catalyzed biaryl coupling, wherein (a) a phenol and arylhalide substrate are converted to a bis-arylether or (b) two arenes are coupled to form a bis-arene species. These coupling reactions are of great importance for general organic synthesis as well as pharmaceutical and fine chemicals. The copper-catalyzed phenol coupling to arrive at chiral biphenol derivatives is used extensively as a test reaction for the catalytic activity of new copper complexes [254,255]. 

IV. ACYLIUM CATIONS IN THE SYNTHESIS OF POLY(ARYLETHER KETONE)S... 

Maier. L.. Organic phosphorus compounds. Part 91. Synthesis and properties of l-amino-2-aryleth-ylphosphonic and -phosphinic acids as well as -phosphine oxides. Phosphorus, Sulfur Silicon Relat. Elem., 53. 43. 1990. 

Interestingly, a first successful extension of the amination to oxygen nucleophils has been reported very recently. [19] Still at the beginning, this discovery opens the door to C-O coupling reactions for the synthesis of arylethers, including oxygen heterocycles. 

Abstract Planar-chiral ri -arene-Cr(CO)3 complexes represent highly valuable buUdlng blocks for the dlastereo- and enantloselectlve synthesis of complex natural products and related bloactlve compounds. Highly original and competitive overall syntheses of various classes of natural products, such as sesquiterpenes, diterpenes, alkaloids and compounds with axial chirality, have been developed. In certain cases, the whole strategy is based on arene chromium chemistry and the various chemical and stereochemical effects of the metal unit are exploited In several subsequent transformations. Cationic Cp-ruthenium complexes allow arylether formation by Sj Ar reactions and have found application in the synthesis of glyco-peptide antibiotics. 

At the end of this chapter, a few cationic arene-RuCp complexes will be mentioned as well, because such complexes possess a unique potential for arylether formation and have thus found convincing application in total synthesis as well. 

Another Ullmann synthesis is the syntheses of arylethers or diarylamines by the condensation reactions of aryl halides with phenols or arylamines. For example, reactions are shown in eqs. (22.16) [62] and (22.17) [63], and especially the former reaction is used for the production of polyphenylether type heat-resistant synthetic lubricants. 

We will start with this category as it is the most common current catrJytic C-H activation process as regards arylation. This section is basically an extension of Chapters 1 to 3, as it concerns the synthesis of biaryls, arylamines, arylethers, arylsulfides, and arylphosphanes, and so on. 

An alternative way for the synthesis of phenols and arylethers is the photosubstitution of the diazo group. This reaction was first reported at the end of the... 

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