A Direct Catalytic Ring Expansion Approach to O-Fluoronaphthols and o/p-Fluorophenols from Indanones and 2-Cyclopentenones.

A direct method for the synthesis of o-fluoronaphthols and o/p-fluorophenols has been developed by a catalytic ring expansion of indanones and 2-cyclopentenones, in which TMSCF2Br was used as a unique :CF2 source, a TMS transfer agent, as well as the Br− and F− releaser for the enolization, difluorocyclopropanation, desilylation, ring opening, defluorination, and aromatization sequence.