Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• ; electrochemistry; emission; helical elongation; helicene; photophysical; Introduction Chirality is a pervasive feature of natural and artificial systems, and chiral small molecules continue to underpin advances in chemistry and materials science [1][2]. Among them, helicenes – ortho-condensed polycyclic aromatic

• progressive increase in aromaticity upon helical elongation compared with the corresponding oxaza[7] analogues (see Supporting Information File 1) [49], as evidenced by NICS(1)zz values of −26.97 and −21.17 for rings E and H in 5a, and −28.86 and −31.74 for rings E′ and H′ in 5b. This enhancement can be

• structures was confirmed by frequency analysis, which revealed no imaginary frequencies. The frontier orbitals are non-degenerate, and the S1 → S0 transition is dominated by the LUMO → HOMO contribution. The oscillator strength of the S1 → S0 transition decreases with helical elongation (Figure 4C), in line