34251-29-1Relevant articles and documents
Azahelicenes from the Oxidative Photocyclization of Boron Hydroxamate Complexes
Murase, Takashi,Suto, Toru,Suzuki, Honoka
, p. 726 - 729 (2017)
Aromatic hydroxamic acids (Ar–CO–NOH–Ar′) were used as bidentate chelating ligands to generate the corresponding boron hydroxamate complexes, which were subsequently transformed into nitrogen-containing helicenes (azahelicenes) using an oxidative photocyclization method that is frequently used for stilbene-type (Ar–CH=CH–Ar′) precursors of carbohelicenes. The nitrogen atom of the hydroxamate linker was thus directly embedded into the helicene core without using nitrogen-containing aromatic rings in the stilbene-type precursors. In a batch photoreaction, aza[4]helicenes were readily and efficiently prepared, but aza[6]helicenes underwent severe decomposition upon irradiation. Alternatively, a continuous flow photoreactor was employed to furnish an amide-type aza[6]helicene.
