Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• aryltetralin[2,3-c]furan skeleton embedded in this natural product. Keywords: aryltetralin; conjugate addition; cyclolignan; nickel; reductive coupling; Introduction Proksch and co-workers isolated aglacins A, B, C, and E (1–4, Figure 1) from the methanolic extract of stem bark of Aglaia cordata Hiern from

• the tropical rain forests of the Kalimantan region (Indonesia) [1][2]. These cyclic ether natural products belong to the typical aryltetralin lignans, which have already attracted broad attention from the synthetic community [3][4][5]. Zhu and co-workers disclosed a concise synthesis of (±)-aglacins B

• ] by flash column chromatography in 30% yield. The stereocontrolled formation of aryltetralin 13 could be attributed to an adoption of a pseudo-half-chair conformation 5a. Finally, the final step towards the total synthesis of (+)-aglacin B (2) was achieved by treatment with BF3·Et2O as the Lewis acid

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• affording intermediary benzyl carbenium ions, which are then trapped by a variety of electron-rich aromatics via Friedel–Crafts alkylation. This cascade Prins/Friedel–Crafts cyclization protocol paves an expedient path to medicinally useful 4-aryltetralin-2-ol and 5-aryltetrahydro-5H-benzo[7]annulen-7-ol

• derivatives. Keywords: 4-aryltetralin-2-ol; 5-aryl-benzo[7]annulen-7-ol; cascade reaction; Prins/Friedel–Crafts; Introduction 2,4-Disubstituted tetralins (Figure 1, 1), especially 2-functionalized tetralins are privileged building blocks for medicinal chemistry applications which are known to exhibit a wide

• attempted alkenyl-aldehydes 13 to furnish the corresponding 2,4-disubstituted tetralins 14ba–hb in acceptable to good isolated yields. For instance, the reaction with aldehydes 13 containing π-donating substituents like methoxy and chloro substituents afforded the 2-hydroxy-4-aryltetralin products 14ba–cb