870. Bisbenzylisoquinolines. Part IV. The preparation of diaryl ethers from diaryliodonium salts

Abstract

The reaction of phenoxides with symmetrically substituted diaryliodonium salts provides a general route to substituted diaryl ethers. This procedure and other methods were used to synthesise the phthalimido-ester [VI : R = CH2*CH2*N(CO)2C6H4-o] and the corresponding amino-acid (VII) . DIARYLIODONIUM SALTS are readily attacked at position 1 by nucleophiles,2 and thus show promise as general electrophilic phenylating agents. The reaction with phenoxides proceeds, apparently, by a variation of the SN2 m e c h a n i~m ,~.~ and gives diphenyl ethers :We have studied the reaction further because of our interest in diphenyl ethers as intermediates in the synthesis of bisbenzylisoquinoline alkaloids. Since only a few examples have been r e p~r t e d ,~* * *~ the reactions of simple iodonium salts were examined first, in order to establish a suitable procedure and to determine the scope of the method. The ( I ; R = Me, X = Br) Guaiacol Me OMe H H 64 (I; R = Me, X = Br) Vanillin Me OMe H CHO 63 (I; R = Me, X = Br) Isovanillin Me OMe CHO H 65The amino-acid (VII) is required in the synthesis of bisbenzylisoquinolines, and one scheme devised for its preparation involved the reaction of the phthalimido-phenol (V) with the 4,4'-di(methoxycarbonylmethyl)diphenyliodonium salt (IV) and hydrolysis of the product [VI ; R = CH,*CH,*N(CO),C,H,-01. Oxidative iodination of methyl phenylacetate followed by addition of the appropriate inorganic salt gave the diaryliodonium bromide, chloride, or iodide (IV). Heating the iodide at 160" or refluxing its solution in

Remarks on the internal motion in diphenyl ether. Fluorophenyl ethers

“…The 2,6-dibromo-4-fluorophenyl phenyl ether was prepared as follows (16). A mixture of 4 g of diphenyl iodonium bromide (Aldrich), 0.44 g of NaOH, 60 mL of H20, and 2,6-dibromo-4-fluorophenol (Aldrich) was heated under reflux for 24 h. The extracted (ether) solution was washed with aqueous NaOH, dried with MgS04, and evaporated to yield a mixture of the desired product and iodobenzene (IH nmr spectrum).…”

Diaryliodonium Salts in Organic Syntheses: A Useful Compound Class for Novel Arylation Strategies

“…Similar to Crowders's work, 12 Olofsson et al also developed a metal-free synthesis of aryl ethers in aqueous media under mild conditions. 16 The reaction employs diaryliodonium salts and sodium hydroxide in water at low temperature.…”

“…In their procedure they used sodium hydride as a base and the reactions were performed in tert-butyl methyl ether (TBME) at 50 °C. N-Aryloximides 21 (13, 14) can be also synthesized with the aid of iodonium salts under transition-metal-free conditions via O-arylation of Nhydroxysuccinimides (11) and N-hydroxyphtalimides (12) in excellent yields in short reaction times (Scheme 7). Several products were synthesized by using both symmetric and unsymmetric iodonium salts.…”

“…Several products were synthesized by using both symmetric and unsymmetric iodonium salts. In case of phtalimide derivatives (12), the obtained chemoselectivity showed that the most electron deficient aryl group, i. e. the phenyl group was transferred with high or complete selectivity and both trimethoxyphenyl and thienyl groups were ideal as nontransferable "dummy" groups. …”

Diaryliodoniumsalze – aus dem Nichts ins Rampenlicht

“…[145] 3.4. [146] Die Methode wurde zur Synthese etlicher polybromierter Diphenylether angewendet, die eine Reihe von industriellen Einsatzgebieten haben. [147] Polymergebundene Diaryliodoniumsalze wurden verwendet, um Diarylether und Thioether in mäßigen bis guten Ausbeuten durch die Reaktion mit Natriumaryloxiden bzw.…”