Substituent effects on the conformational equilibrium of 1,3,5,7-cis-tetraoxadecalin systems: Force field calculations Versus experimental results
摘要:
Conformer populations of a number of 1,3,5,7-cis-tetraoxadecalins have been studied by H-1 NMR spectroscopy. While the unsubstituted 4 prefers the proximal conformation, all 4,8 disubstituted derivatives 5 preferred the distal conformation. This was most marked for the di-azidomethyl derivative 5g. Force field calculations were shown to reproduce only roughly the trends of the conformer equilibria. Changing the solvent from toluene-D-8 to more polar solvents increases the population of the proximal conformer.