The carbonylation of phenyl bromide and its derivatives under visible light irradiation

The carbonylation of phenyl bromide catalyzed by Co(OAc) 2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive. With strong base CH 3 ONa, PhCOOCH 3 is produced in 70% yield with 100% selectivity , the similar results are also obtained with a stronger base (CH 3 ) 3 CONa. However, with another strong base NaOH, the yield of the ester is only 40%. On the other hand, with weak base NaOAc or ( n -C 4 H 9 ) 3 N, phenyl bromide cannot be carbonylated. The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o , m , p -BrC 6 H 4 CH 3 are similar to phenyl bromide, while the activities of o , m , p -BrC 6 H 4 Cl are higher with the high yields (≥93%) of the corresponding chloro-esters. In addition, the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation .