Synthesis, structures and Lewis‐Acid‐Induced isomerization of 8‐Methoxy[2.2]metaparacyclophanes and a DFT study

Islam, Md. Monarul; Feng, Xing; Rahman, Shofiur; Georghiou, Paris E.; Matsumoto, Taisuke; Tanaka, Junji; Alodhayb, Abdullah; Redshaw, Carl; Yamato, Takehiko

Abstract

Methyl substituted 8‐methoxy[2.2]MPCPs 8 a–b were obtained via thiacyclophane and its oxidized products. Lewis acid‐catalyzed (AlCl3‐MeNO2) reactions of 5‐tert‐butyl‐8‐methoxy‐12,13,15,16‐tetramethyl[2.2]MPCP 8 b under various conditions led to transannular cyclization and isomerization reactions, affording the considerably less‐strained 5‐tert‐butyl‐8‐methoxy[2.2]MPCP 9, 5‐tert‐butyl‐8‐hydroxy‐14,16,17,18‐tetramethyl[2.2]metacyclophane 10 and pyrene derivatives 11 and 12. However,on prolonging the reaction time to 3 h for 8 b, the major product is 5‐tert‐butyl‐8‐hydroxy[2.2]MPCP 10. These reactions are strongly affected by the size and properties of the C‐8 substitutents as well as the methyl substitutents on the para‐linked benzene rings, which increase the strain in the molecules. The 1H NMR spectra and X‐ray crystallographic analysis of 8 b revealed that it adopts a syn‐conformation both in solution and in the solid state.

Citation

Islam, M. M., Feng, X., Rahman, S., Georghiou, P. E., Matsumoto, T., Tanaka, J., Alodhayb, A., Redshaw, C., & Yamato, T. (2019). Synthesis, structures and Lewis‐Acid‐Induced isomerization of 8‐Methoxy[2.2]metaparacyclophanes and a DFT study. ChemistrySelect, 4(13), 3630-3635. https://doi.org/10.1002/slct.201900190

• Journal Article Type: Article
• Acceptance Date: Mar 14, 2019
• Online Publication Date: Apr 1, 2019
• Publication Date: Apr 9, 2019
• Deposit Date: Apr 2, 2019
• Publicly Available Date: Apr 2, 2020
• Journal: ChemistrySelect
• Electronic ISSN: 2365-6549
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 13
• Pages: 3630-3635
• DOI: https://doi.org/10.1002/slct.201900190
• Keywords: Isomerization; Lewis acid; Metaparacyclophane; Strain; Transannular reaction; Trans-tert-butylation
• Public URL: https://hull-repository.worktribe.com/output/1527613
• Publisher URL: https://onlinelibrary.wiley.com/doi/full/10.1002/slct.201900190
• Contract Date: Apr 2, 2019