Friedel-Crafts reactions of phenols

The enones 9 are made either by a Friedel-Crafts reaction of phenols and a,P-unsaturated acid chlorides or by a Fries rearrangement of the phenol esters 10. 

Luo et al. exploited the enantioselective Friedel-Crafts reaction of phenols 35 with p,y-unsaturated ot-ketoesters 32 to form compounds 36. In their preliminary studies, they found that neither a phosphoric acid nor magnesium fluoride could catalyse the reaction. However, the combination of a phosphoric acid with magnesium fluoride (4 1 ratio) could efficiently catalyse the reaction in good yields (59-82%) and selectivity (79-99%), but using preformed sodium phosphate with magnesium fluoride resulted in no... 

Scheme 3.10 Friedel-Crafts reactions of phenols or indoles.

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