The Conformational Analysis of 14-Membered Macrocyclic Ethers

The conformational analysis of a series of 14-membered macrocyclic ethers possessing a variety of methyl substitution patterns was performed using both NMR spectroscopy and molecular mechanics calculations. Low temperature DNMR spectra of the macrocyclic ethers were interpreted using van der Waals steric compression and anisotropic shielding effects. The macrocyclic ether transition state energies were determined from the DNMR spectra to be approximately 9–10 kcal/mol and were compared to computer calculated values.