Diarylmethane derivatives compounds

This reaction was initially studied by von Baeyer in 1872. It is an acid-catalyzed condensation of aromatic compounds with formaldehyde or formaldehyde derivatives. In normal conditions, the reactive benzene derivatives such as phenols and arylamines are applied to condense with formaldehyde however, a small number of less-reactive aromatics have also been used in this reaction, including benzene, toluene, benzyl chloride,biphenyl, iodobenzene, naphthalene, and mesitylene. Although no yields were given in the early studies, it is reasonable to obtain 70-80% yield for this type of reaction. Many other reactions have been developed to synthesize diarylmethanes, including Katritzky s benzotriazole method, Kochi s dealkylative coupling," Fukuzaw s 1,3-propandiol method, and the reduction method. In general, the condensation occurs at the /tflra-position of substituted aromatics. 

Trimethylaluminum exhaustively methylates O-functions and thus converts tert. alcohols to alkanes, ketones to gem-dimethyl compounds, and carboxylic acids to terUhuiyX derivatives . AgC104-SnCl4 gives high yields of diarylmethanes by benzylation of arenes, e. g. with benzyl alcohol . 

The alkylation of 2-arylpyridine and 2-aryloxazoline derivatives with benzylhalides leads to regioselective ort/io-monoakylations under similar conditions and to the formation of diarylmethane compounds. However this reaction revealed the surprising higher efficiency of benzylchlorides compared to benzylbromides [(Eq. 35)] [110]. 

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