A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• with a chlorine-containing oxidant (t-BuOCl) in the presence of a base (2,6-lutidine). In addition the basic physicochemical properties of newly synthesized compounds have been investigated. Keywords: aromatic amines; azahelicenes; cinnolines; halogen; oxidation; Introduction Helicenes, ortho-fused

• polycyclic aromatic compounds, have been fascinating organic chemists over the last century since the first synthesis of azahelicenes was reported by Meisenheimer in 1903 [1], not only because of their aesthetically attractive structures, but also because of their unique properties arising from the helical

• functionalized BINAMs except for highly electron-rich substrates to produce functionalized 7,8-diaza[5]helicenes in a single-step from BINAMs. Furthermore, basic properties of the azahelicenes have also been investigated. UV–vis absorption spectra of 2a, 2b, 2d, and 2f. Synthetic routes to 7,8-diaza[5]helicene