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The reaction of arenediazonium tetrafluoroborates with chlorotrimethylsilane in a tetrahydrofuran/N,N-dimethylformamide (DMF) (5v/3v) solution afforded the protodediazotization products in high yields. The reactions of the diazonium salts with halotrimethylsilanes in DMF were found to give the corresponding haloarenes. Among the halodediazotization reactions, the iododediazotization with iodotrimethylsilane proceeded smoothly at room temperature to give the iodoarenes in excellent yields. In a similar manner, a variety of azidoarenes were obtained in consistently high yields by the treatment of arenediazonium tetrafluoroborates with azidotrimethylsilane in a DMF solution.

A new trifluoroacetylating reagent, 2-(trifluoroacetyloxy)pyridine (TFAP), was prepared by the reaction of 2-pyridinol and trifluoroacetic anhydride. TFAP has been found to be effective in the trifluoroacetylation of aliphatic and aromatic amines and alcohols including phenol under mild conditions. The reaction of p-nitrophenol with TFAP in ether gave the hydrogen-bonded complex between the phenol and 2-pyridone. This reagent has also been shown to be useful for the intramolecular dehydration of aldehyde oximes and amides to give nitriles in high yields.

2-(Trifluoroacetoxy)pyridine (TFAP) is useful for trifluoroacetylating arenes under the Friedel–Crafts conditions. Benzene, alkylbenzenes, naphthalene, and dibenzofuran have reacted with TFAP in the presence of aluminum chloride in dichloromethane to give the corresponding trifluoromethyl aryl ketones in good isolated yields.

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