Recently, Ding Du's team in the School of Science published a paper entitled “Enantioselective de novo Construction of Pyran-2-one-fused Helicenoids via NHC” (Very Important Paper, VIP) in the prestigious journal Angew Chem Int Ed. Chenxing Li, a Master's degree student of the School of Science, class of 2023, was the first author of the paper, Prof. Ding Du was the only corresponding author, and China Pharmaceutical University (CPU) was the completion unit of the paper.
Helical chiral molecules are characterized by consecutive neighboring densely packed aromatic or heteroaromatic rings with unique non-planar helical structures and excellent chiral optical properties, which have a wide range of applications in various fields such as molecular recognition, materials science, asymmetric catalysis and medicinal chemistry, and this has inspired chemists to carry out catalytic asymmetric syntheses of spirochiral molecules. However, the development of catalytic asymmetric synthesis methods for spirochiral molecules faces great challenges due to their structural complexity. Among the known methods, transition metal asymmetric catalysis is the most commonly used method to construct spirochiral molecules, but the success of organic asymmetric catalysis is very limited.
To address the above challenges, the team built on previous work (Angew Chem Int Ed, 2022, 61, e202212005; Chem Sci, 2025, 16, 7876) and constructed pyran-2-one thickened [5]spiroenoids and [4]spiroenoids ab initio using an asymmetric (3+3) cyclization strategy catalyzed by nitrogen-heterocyclic carbene organosmall molecules (Figure 1). Racemization experiments showed that the oxaspiroene-like skeleton has high conformational stability and is easy to achieve late functionalization and modification. The synthesized optically pure pyran-2-one thickened spiroallene molecules have good optical physical properties and chiral optical properties (Figure 2), which have potential applications in the field of materials chemistry. This method not only provides a novel strategy for the asymmetric synthesis of oxaspiroene skeletons with potential applications, but also provides a new idea for the organocatalytic asymmetric synthesis of heterospiroene molecules.
The above work was supported by the National Natural Science Foundation of China and the Double First-class Construction Program of China Pharmaceutical University.
Article link: DOI https://doi.org/10.1002/anie.20250878
Organic asymmetric-catalyzed synthesis of chiral pyran-2-one thickened spiroenoids
Photophysical and chiral optical properties of some optically pure compounds
