Herein, we report a new and efficient method for the large scale synthesis
of 2,6-dicarboxyfluorenone 5 in 95% yield using 0.01 mol% of bis(triphenylp
hosphine)palladium(ll) chloride, (PPh3)(2) PdCl2, as a catalyst, starting w
ith the reaction of 2,5-dimethylbromobenzene and 4-bromotoluene to give 2,4
,5-trimethylbiphenyl 3, followed by oxidation and then cyclization.