Palladium-Catalyzed Annulation of Phenazastannines with 9-(Dibromomethylene)fluorene and -(thio)xanthenes: Facile Synthesis of Acridine Moiety-Containing Bis(tricyclic) Aromatic Enes

Abstract

Growing interest has been paid to bis-(tricyclic) aromatic enes as key components of functional organic materials such as molecular switches and chargetransporting materials. Currently, the synthetic approaches to the overcrowded alkenes are limited to McMurry coupling and Barton−Kellog olefination. This communication reports that palladium-catalyzed double cross-coupling reaction of phenazastannines with 9-(dibromomethylene)fluorene, -xanthene, -thioxanthene, and -thioxanthene-S,S-dioxide serves as a facile synthetic approach to bis(tricyclic) aromatic enes such as 9-(9Hfluoren-9-ylidene)acridines, 9-(9H-oxanthen-9-ylidene)acridines, 9-(9H-thioxanthen-9-ylidene)acridines, and 9-(10,10-dioxido-9H-thioxanthen-9-ylidene)acridines.

Dimeric tetrabromo-p-quinodimethanes: synthesis and structural/electronic properties

“…3,4 Besides their use in FBW rearrangements, this functionality has found use in the synthesis of [4]radialene. 5 Nonetheless, it is as substrates for palladium cross-coupling reactions where gem -dibromoolefines have found a broader use, allowing Suzuki, 6 Stille 7 and Sonogashira couplings. 8 When the gem -dibromoolefines are stemming from p -quinones, the resulting tetrabromo- p -quinodimethanes ( TBQ s) may undergo dehalogenative homocoupling on coinage metal surfaces, namely Au(111) and Ag(111), forming one-dimensional (1D) acene and periacene polymers that may exhibit appealing non-trivial topological electronic properties, depending upon the acene nature and length of the polymer.…”