The synthesis of palladacyclopentadienyl derivatives from rigid bis-alkynes and their use as precursors in the synthesis of fluoroanthene-like cycles under mild conditions. A reactivity investigation

The palladium(0) derivatives of the type [Pd(η2-ol)(LL′)] (2) (ol = dmfu: dimethylfumarate (a), fn: fumaronitrile (b), tmetc: tetramethylethylenetetracarboxylate (c), LL′ = HNSPh: 2-(phenylthiomethyl)-pyridine (A), BiPy: 2,2′-bipyridyl (B), DPPE: bis-diphenylphosphinoethane (C)) were reacted in CH2Cl2 with 1,8-bis(methylpropynoate)naphthalene (1) and 2,2′-bis(methylpropynoate)biphenyl (1′). At variance with the flexible 1′ derivative, the rigid bis-alkyne 1 reacts smoothly to give the corresponding cyclopalladate complexes [PdC4(COOMe)2(Ph)2(LL′)] (3). The rates of reaction were determined and the X-ray diffraction structure of the complex [PdC4(COOMe)2(Ph)2(HNSPh )] (3A) is reported. The reactivity of the complexes [PdC4(COOMe)2(Ph)2(LL′)] (LL′ = HNSPh (3A), BiPy (3B), DPPE (3C)) was studied by reacting these complexes with fn and tetracyanoethylene (tcne), respectively. The ensuing fluoroanthene-like compounds were fully characterized.