Fries rearrangement clays

Venkatachalapathy, C., Pitchumani, K. Fries rearrangement of esters in montmorillonite clays steric control on selectivity. Tetrahedron... 

Although much attention has been recently given to zeolites in the area of catalysis (petrochemistry in particular), there are few examples in the literature of the utilisation of solid acids such as clay (ref. 2) or zeolite (ref. 3) catalysts to the acylation of aromatics. On the other hand, the Fries rearrangement of phenylacetate has been well described (ref. 4). 

Table 5.14 Clay-promoted Fries rearrangement of phenyl and 1-naphthyl esters at 140°C for 5 h...

Bolognini, M., Cavani, F, Cimini, M., Dal Pozzo, L., Maselli, L., Venerito, D., Pizzoli, F, and Veronesi, G. 2004. An environmentally friendly s)mthesis of 2,4-dihydroxybenzophenone by the single-step O-mono-benzoylation of 1,3-dihydroxybenzene (resorcinol) and Fries rearrangement of intermediate resorcinol monobenzoate the activity of acid-treated montmorillonite clay catalysts. C. R. Chim. 7 143-150. 

Also using K-10 clay as a support, an experiment illustrating the Fries rearrangement has been reported for use in an undergraduate laboratory, in which the P-napthylacetate and the steroid estrone are used as substrates (Scheme 6.7). Drawbacks, however, are the use of a domestic microwave, open beakers as reaction vessels, and the vague experimental details provided. The protocol calls for heating the reaction at power level 9 for 10 min. In the absence of temperature data, it would be hard to reproduce the experiment without reoptimization. 

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