Preparation of 3,4-Fused Cyclopropabenzenes and Cyclopropabenzenyl Cations

A series of 3,4-disubstituted ( 4a , b ) or 3,4-fused ( 4c - e ) 1,1-di-fluorocyclopropabenzenes, including the very strained 1,1-difluoro-3,4-dihydro-1 H-cyclobutaa]cyclopropad]benzene ( 4e ) have been synthesized and characterized. Dissolution of these difluoro derivatives in fluorosulfonic acid affords the fluoro cations 3a – e . ¹H-, ¹⁹F-, and ¹³C-NMR data of the cations are reported and discussed with respect to those of the precursors.