Iodination of 2,3-diphenylbenzo [b]furans 1a-c with molecular iodine i
n the presence of red mercuric oxide gives rise exclusively and effici
ently to the corresponding 6-iododerivatives 2a-c. The UV irradiation
of these compounds in benzene solution affords the 6-phenylated compou
nds 3a-c, which give the 11-phenylbenzo[b]phenanthro[9,10-d]furans 4a-
c by photocyclisation. The strong fluorescence of these compounds is s
tudied.