Aryl ethers nucleophilic aromatic substitution

The reaction between an alkoxide ion and an aryl halide can be used to prepare alkyl aryl ethers only when the aryl halide is one that reacts rapidly by the addition-elim mation mechanism of nucleophilic aromatic substitution (Section 23 6)... 

A one-pot three-step conversion of aryl fluorides to phenols based on a consecutive nucleophilic aromatic substitution/isomerization/hydrolysis sequence has been reported by Levin and Du (Scheme 6.126) [256], The authors discovered that 2-butyn-l-ol can function as a hydroxyl synthon through consecutive SNAr displacement, in situ isomerization to the allenyl ether, and subsequent hydrolysis, to afford phenols rapidly and in good yields. In most cases, excesses of 2-butyn-l-ol (1-2 equivalents) and potassium tert-butoxidc (2-4 equivalents) were required in order to achieve optimum yields. 

We initiated our work by examining nucleophilic aromatic substitution, a somewhat difficult reaction to effect in other than activated aryl halides as substrates. It occurred to us that if polyhaloaromatics could be made to suffer disubstitution under mild solid-liquid PTC conditions, then they might be used as comonomers with a variety of bisnucliophiles to prepare halogenated polyaryl-ethers, sulfides, sulfone-ethers as well as other interesting polymers which are at present synthesized only with some difficulty. 

The aryl halide must be one that is reactive toward nucleophilic aromatic substitution by the addition-elimination mechanism. p-Fluoronitrobenzene is far more reactive than fluorobenzene. The reaction shown yields p-nitrophenyl phenyl ether in 92% yield. 

An early report of the beneficial influence of 1,1-diphenylethylene (DPE) on the yields of alkylaryl ether obtained in the reaction of diaryliodonium salts with sodium alkoxides showed that radical chain reactions compete efficiently with the 0-arylation reaction. By contrast, addition of diphenylpicrylhydrazyl, a stable free radical species, had no significant influence on the yields of products obtained in e absence of additives. In this case, the 0-arylation reaction was considered to be a direct nucleophilic aromatic substitution reaction, without the involvement of any transient covalent intermediate. (Table 2.11)... 

D. M. Knauss and J. B. Edson. Poly(aryl ether sulfide)s by sulfide-activated nucleophilic aromatic substitution polymerization. Polymer, 47(11) 3996-4003, May 2006. 

J. B. Edson and D. M. Knauss. Thianthrene as an activating group for the synthesis of poly(aryl ether thianthrene)s by nucleophilic aromatic substitution. J. Polym. Set, Part A Polym. Chem., 42(24) 6353-6363, December 2004. 

Guo et al. [180] prepared a series of sulfonated poly(aryl ether ketone) copolymers (Br-SPAEKs) by nucleophilic aromatic substitution reaction based on (6F-BPA, A2 monomer), 4,4 -DFBP, unsulfonated B2 monomer), 3,3 -disodiumsulfonyl-4,4-difluoro-benzophenone (SDFBP, sulfonated B2 monomer), and 2,4, 6-trifluoro-benzophenone (TFBP, branched... 

R.N. Johnson, A.G. Famham, R.A. Clendinning, WF. Hale, C.N. Merrian, Poly(aryl ethers) by nucleophilic aromatic substitution. I. Synthesis and properties, J. Polym. Sci. Part A Polym. Chem. 5 (9) (1967) 2375-2398. 

R, N. Johnson, A. G. Farnham, R. A. Clendinning, W. F. Hale and C. N. Mer-riam, "Poly(aryl)ethers by Nucleophilic Aromatic Substitution. I. Synthesis and Properties", J. Polymer Science, Part A-1, Vol. 2375-2398 (1967). 

Nucleophilic aromatic substitution reactions of haloarenes complexed to transition metal moieties with oxygen-, sulfin-, and nitrogen-containing nucleophiles allows for the synthesis of a wide variety of aryl ethers, thioethers, and amines. These metal-mediated reactions proceed under very mild conditions and allow for the incorporation of a number of different functional groups. Nucleophilic substitution reactions of chloroarenes complexed to the cyclopentadienyliron moiety have been the focus of many studies directed toward the design of functionalized organic monomers. ... 

The Ullmann reaction can be taken to refer to two different transformations. The first is the copper mediated coupling of two aryl groups to give a biaryl compound this is the classic Ullmann reaction. The second, the Ullmann-type reaction, is the nucleophilic aromatic substitution between aryl nucleophiles and aryl halides, the most common of which is the Ullmann ether synthesis. The classic Ullmann reaction will be reviewed in this chapter the reader is refered to several excellent reviews for details on the Ullmann-type reaction. " ... 

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