trifluoroacetic acid 5 h; Heating;

aluminium trichloride in dichloromethane T=20°C; 3 h; further solvents: various nitro- and chloro-hydrocarbons; Product distribution;

trifluoroacetic anhydride in trifluoroacetic acid 10 h; Heatingpositional reactivity of dibenzofuran in electrophilic substitutions; similar isomer distribution under Friedel-Crafts acylation conditions, other reagents, solvents, temperatures; Product distribution;