Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact:

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

Paper | Regular issue | Vol 53, No. 1, 2000, pp.27-35
Published online, 1st January, 1970
DOI: 10.3987/COM-99-8705
[N](3,5)Isoxazolophanes: Dynamic Behavior and Reaction with Electron-deficient Acetylene Leading to [N](2,6)Pyridinophanes

Hiroyuki Yamamoto and Makoto Nitta*

*Department of Chemistry, School of Science and Engineering, Materials Research Laboratory for Bioscience and Photonics, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan


1H NMR spectroscopy at various temperatures clarified the dynamic behavior of the oligomethylene chains for [8](3,5)isoxazolophane (1) and unsubstituted and 4-methyl-substituted [9](3,5)isoxazolophanes (2a,b). The energy barriers (ΔGc) for the bridge flipping are 18.6 kcalmol-1 (Tc 100 °C) for 1 and 11.5 kcalmol-1 (Tc-10 °C) for 2a. Compound (2b) does not undergo bridge flipping in temperatures ranging from 25 °C to 150 °C. The energy barriers for the pseudorotation are 11.1-11.2 kcalmol-1 (Tc -10 °C), 9.1 kcalmol-1 (Tc-70 °C), and 8.6 kcalmol-1 (Tc-80 °C) for 1, 2a, and 2b, respectively. The Mo(CO)6-induced reaction of 2a,b with dimethyl acetylenedicarboxylate afforded [9](2,6)pyridinophane derivatives, albeit in low yields.