Conformations in solution of four 2,4,5,7‐tetramethyloctane‐4,5‐dicarboxylates: Molecular mechanics and NMR studies

Abstract

Potential energy calculations (MM2), low‐temperature 1H and 13C NMR spectra and 1H–1H COSY spectra are reported for four octane derivatives, the central portions of which constitute tetrasubstituted succinates. The existence of several conformers differing in stereochemistry in this central moiety is predicted by calculations and observed in low‐temperature NMR. The periphery of each molecule is in an extended configuration, as shown by the existence of long‐range (W‐plan) couplings involving the methyl groups. Copyright © 1991 John Wiley & Sons Ltd.