Oxalyl chloride, complexes with aromatics

The mono- and poly-alkylated benzenes are treated using modifications of the above procedure. Monoalkylbenzenes are added to a preformed complex of acyl halides and aluminum chloride in carbon tetrachloride (Perrier modification). In this manner, the manipulation is easier, no tars are encountered, and the yields are improved (85-90%). The procedure shows no advantage, however, in the acylation of alkoxy- or chloro-aromatic compounds. The addition of benzoyl chloride to p-alkylbenzenes in the presence of aluminum chloride in cold carbon disulfide is a good procedure for making p-alkylbenzophenones (67-87%). The condensation of homologs of benzene with oxalyl chloride under similar conditions yields p,p -di alkylbenzophenones (30-55%). Polyalkylbenzenes have been acylated with acetic anhydride and aluminum chloride (2.1 1 molar ratio) in carbon disulfide in 54-80% yields. Ferric chloride catalyst has been used under similar conditions. Acetylation of p-cymene with acetyl chloride and aluminum chloride in carbon disulfide yields 2-methyl-5-isopropylaceto-phenone (55%). ... 

Very electron-rich aromatic systems interact with acid chlorides and anhydrides in the absence of a catalyst to afford good yields of ketones. Reactions of pyrrole and substituted pyrroles exemplify these reactions. The oxalylation shown in equation (18) was part of the synthesis of a complex, highly functionalized antitumor agent. Use of the triisopropylsilyl group to direct reaction to the 3-position (equation 19) is noteworthy. ... 

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