Arenediazonium salts, coupling with

Dimethylfuran-3(2ff)-one undergoes coupling with arenediazonium salts at pH 0 and furnishes 2-arylazo-2,5-dimethylfuran-3(2//)-ones which are readily converted into 1 -aryl-5-methyl-3-pyrazolones (79S283). 

Symmetrical stilbenes are obtained by using vinyltriethoxysilane to couple with arenediazonium salts. 1-Ethoxy-1-trimethylsiloxycyclopropane reacts with PhjIBF to give either ethyl cinnamate or the dihydrocinnamate, depending on the order of mixing ... 

Dihydro-3//-pyrazol-3-ones couple with arenediazonium salts in alkaline solution to give azo compounds with the dihydropyrazole ring in the OH-form, e.g. ... 

Sonogashira-Hagihara Cross-Coupling with Arenediazonium Salts - Synthesis of 1-(4-Methoxyphenyl)-2-phenylacetylene... 

Barbituric acid can be considered as a cyclized malonic acid diamide (malonyl-urea). It is therefore a cyclic diketone that may be classified, in the sense of the compounds discussed in Section 12.6, as a coupling component with a methylene group activated by two carbonyl groups in the a- and a -positions. The reaction with arenediazonium salts was studied by Nesynov and Besprozvannaya (1971). These authors obtained coupling products (in good yield) that they considered to be arylhydrazones. Coupling with 4-(phenylazo)benzenediazonium chloride was studied by Chandra and Thosh (1991). The lH NMR spectra of these compounds are consistent with the arylhydrazone structure 12.68. 

In a very recent work, the Pd-catalysed cross-coupling reactions with arenediazonium salts under aerobic conditions in the presence of a chiral monothiourea ligand were reported (Scheme 25) [106]. Even if this Hgand bears four chiral centres, no test in asymmetric Heck-type reaction has been described so far. 

Through the use of arenediazonium salts, the straightforward transformation of amines into cross-coupling products can be realized. Whenever the diazonium salts do not tolerate bases and strong nucleophiles (e.g., phosphines), base- and phosphine-free protocols have to be used. Heterocyclic carbene ligands serve well in cross-coupling of Aryl- and vinylboronic acids, or alkylboronates with arenediazonium salts.369,370 Several convenient phosphine-free protocols have been developed for the same purpose.371-373... 

Apart from imidazol-2-ylidene carbenes, other electron-rich carbenes such as (L27)—generated by deprotonation of a 4,5-dihydroimidazole—have been tested for cross-coupling reactions, but gave much poorer results. The only reported exception is in the cross-coupling of arenediazonium salts with arylboronic acids, in which (L27) (used as hydrochloride) proved to be efficient.369... 

The rate and yield of electrophilic coupling of arenediazonium salts with tt-excessive aromatic systems has been found to be enhanced by the addition of tetra-n-butylammonium bromide [56]. 

Carbonylative cross-coupling of arenediazonium salts with arylboronic or styrylboronic acids was realized using a... 

Palladium catalysts have been found which are effective in the Suzuki coupling reaction of arylboronic acids with aryl chlorides carrying electron-withdrawing groups.73 Biaryls may also be synthesized by cross-coupling of arylboronic acids with arenediazonium salts.74,75 There has been a report of the polymer-bound palladium-catalysed Suzuki coupling of aryl triflates with organoboron compounds.76 Arylbor-onates may themselves be synthesized by the palladium-catalysed reactions of... 

Some of the examples where a diazo or a diazonium compound reacts with activated double bonds, specifically with enamines and with 1,2-dimethoxy-ethene have been mentioned in sections 2.1.2 and 2.1.4, respectively (12, 29). A similar reaction is the azo coupling of arenediazonium salts with tropolones (34) The diazonio group reacts at the C-5 atom, so the reaction is used as a diagnostic tool for the presence of substituents at C-5, as well as for the synthesis of 5-amino tropolones by reduction of the azo compound. 

Suzuki and other couplings. This Suzuki coupling has been applied to preparation of 2- and 4-arylpyridines. For a synthesis of styrenes the coupling of arenediazonium salts with potassium vinyltrifluoroborate has been developed. The latter is a. stable and efficient vinylating agent. 

Aryl-2//-cyclopenta[e][l,2,3,4]tetrazincs 3 are formed by coupling of the diazocyclopentadi-enes 1 with arenediazonium salts and subsequent reversible electrocyclization of the primary coupling products 2.37 Front the solution of the equilibrium mixture of 2 and 3 the colored tetrazines 3 crystallize. 2-Methyl-277-cyclopenta[e][l,2,3,4]tetrazines 3(R2 = Me) are obtained by addition of methyllithium to 1 followed by a diazo transfer reaction and cyclization.37... 

Diazo coupling Electrophilic substitution with arenediazonium salts, giving uzo dyes. 

Azodiazocyclopentadienes 23, the open-chain tautomers of 27/-cyclopenta[/]-l,2,3,4-tetrazines 10, were generated through coupling of arenediazonium salts with diazocyclopentadienes, or via reaction of diazocyclopentadienes... 

Kikukawa, K. Kono, K. Wada, F. Matsuda, T. (1983) Palladium catalysed carbon-carbon coupling of arenediazonium salts with organotin compounds, J. Org. Chem., 48, 1333-6. 

Bumagin, N.A. Sukhomlinova, L.I. Tolstaya, T.P. Vanchikov, A.N., Beletskaya, I.P. (1990) Palladium-catalyzed cross-coupling of arenediazonium salts with tetramethyltin in aqueous media, 7zv. Akad. Nauk SSSR, Ser. Khim., 2665-6. 

ELECTROPHILIC SUBSTITUTION WITH ARENEDIAZONIUM SALTS DIAZO COUPLING... 

SCHEME 4.196 Palladium-catalyzed coupling of arenediazonium salts with secondary phosphine oxides [292]. 

Arenediazonium salts are also used for the couplina[563], (Z)-Stilbene was obtained unexpectedly by the reaction of the ti-stannylstyrene 694 by addition-elimination. This is a good preparative method for cu-stilbene[564]. The rather inactive aryl chloride 695 can be used for coupling with organostannanes by the coordination of Cr(CO)3 on aromatic rings[3.565]. 

Arenediazonium salts undergo a coupling reaction with activated aromatic rings such as phenols and arylamines to yield brightly colored azo compounds, Ar—N=N—Ar. ... 

Arylamines are converted by diazotization with nitrous acid into arenediazonium salts, ArN2+ X-. The diazonio group can then be replaced by many other substituents in the Sandmeyer reaction to give a wide variety of substituted aromatic compounds. Aryl chlorides, bromides, iodides, and nitriles can be prepared from arenediazonium salts, as can arenes and phenols. In addition to their reactivity toward substitution reactions, diazonium salts undergo coupling with phenols and arylamines to give brightly colored azo dyes. 

The P-coupling of 1,2- and 1,4-quinonediazides with phosphines (mainly tri-phenylphosphine) was studied intensively in the 1960s by the groups of Ried and Horner (see summary by Ershov et al., 1981, p. 147). The azo derivatives formed in these reactions are more stable than those of arenediazonium salts because of the stabilization by mesomeric delocalization (6.35 a ++ 6,35 b). 

In the first paper on arenediazonium salt/crown ether complexes, Gokel and Cram (1973) mention that they were not able to synthesize the rotaxane 11.14 by an azo coupling reaction of the complexed diazonium ion with Af,Af-dimethylaniline. 

Arenediazonium salts also couple in acetonitrile with another group of activated ethene derivatives, the allylsilanes (Mayr and Grimm, 1992). At low temperatures the... 

There are amines such as A-methylnitroamine, that are too weakly nucleophilic to be able to form covalent adducts with arenediazonium ions. The products of the latter appear to be those of salts ArNJ N(N02)CH3, as found by Baranchik et al. (1957). Amides also appear not to be sufficiently nucleophilic, but thioamides are, as is shown by the reaction of A-phenylthiourea in the presence of NaOH (Scheme 13-12 Nesynov et al., 1970). First a (probably homolytic) phenylation-de-diazoniation takes place, followed by A-coupling. Selenourea also reacts a mixture of products is formed, which indicates a reaction of the same type as with thiourea (Nesynov and Aldokhina, 1976). 

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