title: A fragment based approach toward thia[n]helicenes.
abstract: The synthesis of [9]- and [11]thiahelicenes, as well as the preparation of lower homologues such as [5]-, [6]-, and [7]thiahelicenes is reported. Efficient palladium catalyzed coupling reactions were employed. Triorganoindium derivatives were selectively mono-cross-coupled with N-methyl-3,4-dibromomaleimide followed by Stille coupling with the readily available building block naphthodithiophene. Oxidative photocyclization of the conjugated precursors using visible light was employed to synthesize a series of thia[n]helicenes. This modular synthetic methodology is independent of the length of the helical backbone.
authors.affiliation: Molecular Design and Synthesis, Department of Chemistry, KU Leuven , Celestijnenlaan 200F, 3001 Leuven, Belgium.
authors.forename: Deepali
authors.initials: D
authors.lastname: Waghray
authors.forename: Wim
authors.initials: W
authors.lastname: Dehaen