Aroyl halide arene

The original reaction procedures have steadily been extended and improved, and an overwhelming number of catalyst systems are now known. Besides aryl halides, many additional substrates, for example aryl triflates, diazonium salts, sulfonyl and aroyl halides, carboxylic and phosphonic acids, and even arenes have been used as... 

Blaser and Spencer used aroyl halides in place of aryl halides, with aroyl chlorides being of specific interest as ubiquitous, relatively cheap compounds ( Blaser reaction ) [24], This latter reaction is normally conducted in aromatic solvents phosphines are not used here as catalyst ligands since they fully inhibit the reaction. In the same way, benzoic acid anhydrides can be used as the aryl source in combination with PdCl2 and catalytic amounts of NaBr [79]. In this reaction, one of the arenes is used in the coupling reaction by elimination of CO, whereas the other benzoate serves as the base. The benzoic acid thus formed can easily be recycled into the anhydride. The use of aryl and vinyl triflates according to Cacchi [25] and Stille [26] extends the scope of the Heck coupling to carbonyl compounds phenol derivatives act via triflate functionalization as synthetic equivalents of the aryl halides. The arylation of cyclic alkenes [27], electron-rich vinyl ethers [28], and allylic alcohols [29] is accessible through Heck reactions. Allylic alcohols yield C-C-saturated carbonyl compounds (aldehydes) for mechanistic reasons (y9-H elimination), as exemplified in eq. (6). 

The reactions of calix[4]arenes with acyl or aroyl halides in the presence of AICI3 yields either the tetraester (i.e. with 4 )28s qj. A,C-diester (i.e. with mono-p-(cyanomethyl)calix[4]arene, the difference being attributable either to the p-substituent and/or the solvent (CH2CI2 in the first case CH2CI2/DMF in the second case). With mono-p-(cyanomethyl)calix[4]arene 122 the diben-... 

The OH groups at the lower-rim of the calixarenes provide a ready handle for the introduction of substituents, and numerous esters and ethers have been made in this laboratory and elsewhere. The aroylation of calix[4]arenes has now been studied in some detail using the aroyl halides shown in Table I. The conformations of the products have been determined by H NMR measurements. The product mixtures... 

Special thiol carboxylic esters (29) were prepared fiom aroyl halides and arene thiolates. These 4,4 -disubstituted S-aiyl arenecarbothioates might gain importance hrtnn a practical point of view, since they exhibit liquid crystal properties and could be useful as components of a di lay cell. Another thiocarboxylic ester (30), which was obtained from a zinc thiochelate and benzoyl chloride (equation 19), might be potentiaUy useful as a precursor for organic conductors. 

Carboxylic acid fluorides, intermediates in the pathway to trifluoromethyl derivatives, are readily formed in reactions of all types of carboxylic acids with sulfur tetrafluoride derivatives (see Section 8.2.4.). Little attention has been paid to fluorination of other carboxylic acid halides. Aroyl chlorides are converted into aroyl fluorides by treatment with sulfur tetrafluoride, e.g. formation of l,41 or to (trifluoromethyl)arenes, e.g. 2 and 3. in the presence of hydrogen fluoride.45 Chlorination of the aromatic ring occurs in some cases.41... 

Friedel-Crafts reaction of arenes with a-chloro-a-(methylthio)acetophenones [19], When A -phenylbenzimidoyl chlorides are aroylated with an aryl halide in the presence of a catalytic amount of an azoliuni salt (such as 1,3-dimethylimidazolium iodide) and sodium hydride, followed by acid treatment in TUF, unsymmetrical benzils can be isolated in 80-92% yields [201. Added to this method is the sequence ketone enaminoketone a-diketone, which cleaves a carbon-carbon double bond in the final stage by photooxygenation [21]. 

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