Synthesis of 2-Hydroxy-2'-aroyl-1,1'-biaryls via Oxidative Ring-Opening of 9 H -Fluoren-9-ols.

An Oxone-mediated oxidative ring-opening reaction of 4,5-disubstituted 9 H -fluoren-9-ols by cleavage of a carbon-carbon bond is reported. 2-Hydroxy-2'-aroyl-1,1'-biaryls can be efficiently prepared by simply heating the mixture of fluoren-9-ols, Oxone, and 1,1,1,3,3,3-hexafluoroisopropanol at 60 °C for 4 h. The persulfate-involved ring-expansion processes were proposed and supported by the DFT calculations.