The conformational analysis of 14-membered macrocyclic ethers

The conformational analysis of a series of 14-membered macrocyclic ethers p ossessing a variety of methyl substitution patterns was performed using bot h NMR spectroscopy and molecular mechanics calculations. Low temperature DN MR spectra of the macrocyclic ethers were interpreted using van der Waals s teric compression and anisotropic shielding effects. The macrocyclic ether transition state energies were determined from the DNMR spectra to be appro ximately 9-10 kcal/mol and were compared to computer calculated values. (C) 2000 Elsevier Science Ltd. All rights reserved.