The structure, modelling and dynamics of 2,7-diisopropoxy-1,8-diarylnaphthalenes

Thirsk, C.; Hawkes, G.E.; Kroemer, R.T.; Liedl, K.R.; Loerting, T.; Nasser, R.; Pritchard, R.G.; Steele, M.; Warren, J.E.; Whiting, A.

Abstract

2,7-Diisopropoxy-1,8-dibromonaphthalene 5 was prepared in two steps from 2,7-dihydroxynaphthalene and was coupled under Suzuki cross-coupling conditions with boronic acids 9 and 10 to provide the corresponding 1,8-diarylnaphthalene systems 12a and 13a respectively. In contrast, attempted coupling of dibromide 5 with o-tolylboronic acid 11 proved unrewarding. Single crystal X-ray structure determination of compounds 12a and 13a showed that both structures possessed a high degree of structural deformation due to high internal steric repulsions between the 1,8-diaryl rings and their substituents. Dynamic H-1 NMR experiments showed that these two systems possessed very slow phenyl-naphthalene bond rotation (ca. 2 s(-1)), corresponding to rotation barriers (DeltaG*) of 16-18 kcal mol(-1). Molecular modelling predicts that such systems have approximately similar rotation barriers and that in order to completely prevent phenyl-naphthalene bond rotation, an ortho-phenyl substituent is required, with a barrier to rotation of ca. 40 kcal mol(-1).

Citation

Thirsk, C., Hawkes, G., Kroemer, R., Liedl, K., Loerting, T., Nasser, R., …Whiting, A. (2002). The structure, modelling and dynamics of 2,7-diisopropoxy-1,8-diarylnaphthalenes. Journal of the Chemical Society-Perkin Transactions 2, 1510-1519

• Journal Article Type: Article
• Publication Date: 2002
• Journal: Journal of the Chemical Society, Perkin Transactions 2
• Print ISSN: 1470-1820
• Peer Reviewed: Peer Reviewed
• Issue: 9
• Pages: 1510-1519
• Public URL: https://durham-repository.worktribe.com/output/1592534