Haloalkylation arenes

Haloalkylation of arenes by unsymmetrical or mixed halides occurs when one of the halogen atoms has a greater reactivity towards the Lewis acid catalyst. It is then possible to isolate the comparatively less reactive haloalkylated products. An example is the reaction of chloroform with benzene in the presence of AICI3. The major product (90%) is dichlorodiphenylmethane (equation 80). ... 

The reactions between Y-(co-haloalkyl)phthalimides and sodium dialkyl phosphite were reported as early as 1949 by Chavane in the successful sytheses of several (co-aminoalkyl)phosphonic diesters. The advantage over the Michaelis-Arbuzov reaction in the preparation of (2-aminoethyl)phosphonic diesters with Y-alkyl or Y-silvl substituents is worth recalling, and several reports of its successful use may be noted, including the preparation of nitrogen-functionalized polyphosphonic esters (Scheme 17). Other substrates for the reaction have included l,3-bis(bromomethyl)benzene and 4-(co-bromoalkyl)arenes ... 

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