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Synthesis and Structural Elucidation of Diversely Functionalized 5, 10-Diaza[5]Helicenes

Diversely functionalized diaza[5]helicenes have been synthesized starting from 6, 9-dichloro-5, 10-diaza[5]helicene, which was prepared from a readily available quinoline building block via Wittig reaction followed by photochemical electrocyclization. The helicene skeleton was substituted by a variety of O-, S-, N-, and C- centered nucleophiles using nucleophilic aromatic substitution reactions and palladium-catalyzed reactions like Suzuki coupling and Buchwald −Hartwig aminations. We have determined, using X- ray single-crystal diffraction, the crystal structures of the chloro- and methoxysubstituted diaza[5]helicenes. A resolution strategy based on diastereomeric separation by substitution of the dichloro derivative with a chiral amine has been shown.

diaza[5]helicenes; Wittig reaction; photochemical electrocyclization

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