Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• , the application of CPA catalysis in the asymmetric synthesis of other forms of molecular chirality has received less attention. While List and co-workers reported the first CPA-catalyzed asymmetric synthesis of helically chiral azahelicenes through the Fischer indole synthesis back in 2014 [12], the

• and polycyclic ketone 2, they achieved the efficient asymmetric synthesis of various helically chiral azahelicenes 3 (Scheme 1). To address the inherent length-scale challenges of molecular helicene frameworks, the authors designed and synthesized novel CPAs bearing extended π-substituents at the

• aromatization process, in 2023 our group reported the asymmetric synthesis of various azahelicenes 8 from polycyclic arylamines 5, dienamides 6 and aldehydes 7 (Scheme 2) [13]. This methodology demonstrates a broad substrate scope, enabling the efficient asymmetric synthesis of diverse aza[5]helicenes 8a–d and

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• helical architectures, have attracted considerable attention due to their intrinsic chirality and tunable optoelectronic properties. Among them, nitrogen-doped helicenes (azahelicenes) and their heteroatom-co-doped counterparts – such as B/N-, O/N-, S/N-, and Se/N-doped helicenes – have emerged as highly

• fluorescence (TADF), and chiral sensing. Notably, recent developments have yielded π-extended, structurally robust, and stimuli-responsive azahelicenes exhibiting record-high dissymmetry factors (|gabs| and |glum|), elevated CPL brightness (BCPL), and efficient integration into CPL-OLEDs and redox-switchable

• applications in asymmetric catalysis [1][2], molecular recognition [3], and organic electronics [4][5]. In recent years, the incorporation of heteroatoms – particularly nitrogen – into the helicene backbone, giving rise to so-called "azahelicenes", has emerged as a powerful strategy to modulate electronic

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