Diarylmethane derivatives reaction with

In 1884, Friedel and Crafts reported that the alkylation of benzene or toluene with dichloromethane in the presence of AlCb avoided the corresponding diarylmethanes, besides other products derived from further alkylation and other transformations. pr ucts from the reaction with benzene are shown... 

In this field, Yoshida et al. have also made interesting contributions describing some insertion reaction of aiynes into C—C a-bonds. IMth /i-toluenesulfonylacetonitrile or malononitrile two equivalents of the corresponding arynes react with the starting material. The overall process, which takes place through an initial C—C a-bond insertion, involves the formation of three C—C and one C—H bonds, and affords diverse diarylmethane derivatives 82 in a straightforward manner (Schane 12.43) [72]. 

Encouraged by these results, the reaction of benzylic alkoxides with dichloroborane was examined. These reactions provide an alternative route to diarylmethane derivatives (Schane 23.77). The deoxygenation of alkoxides using dichloroborane provides useful evidence for understanding the importance of Lewis acidity in previously reported deoxygenation methods operating through alkoxide intermediates. ... 

When paraformaldehyde is added to a solution of II in concentrated sulfuric acid at room temperature, a rapid reaction takes place, yielding colorless to orange polymeric compositions depending upon the ratio of reactants and the reaction condition employed (17). It is reasonable to assume that the polymerization of II with formaldehyde proceeds in a fashion similar to that of an activated aromatic ring with formaldehyde to yield as final products the diarylmethane and dimethylene oxy-derivatives, IV and V (Equation 9). 

Negishi, E., King, A. O., Okukado, N. Selective carbon-carbon bond formation via transition metal catalysis. 3. A highly selective synthesis of unsymmetrical biaryls and diarylmethanes by the nickel- or palladium-catalyzed reaction of aryl- and benzylzinc derivatives with aryl halides. J. Org. Chem. 1977,42, 1821-1823. 

Unsymmetrical biaryh and diarylmethanes. Negishi et al have used a nickel-(0) complex or a palladium(0) complex as catalyst for the cross-coupling of aryl-or benzylzinc halides with aryl halides at room temperature to form biaryls or diarylmethanes. The zinc derivatives are prepared by reaction of aryl- or benzyl-lithium with zinc chloride or bromide. 

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. 

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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