For new ladder-type oligomers and polymers with versatile
and robust
synthetic strategies, in this study, four fully conjugated ladder-type
overcrowded 9,9′-bifluorenylidene-based compounds and oligomers
(BFY1, BFY2, BFY3, and BFY4) were synthesized via a Pd-catalyzed tandem Suzuki coupling/Heck
cyclization reaction. By monomer screening and route optimization,
the target products were obtained in high yields and characterized
by 1H and 13C NMR spectroscopy and high resolution
mass spectroscopy.