Conformation preferences in 2,4,6-trisubstituted heptanes

The preference of (2R*,4r*,6S*)-2,4,6-trichloroheptane (6) for populating the fully extended conformation mirrors the local conformational preferences of the 2,4-dichloropentane subunits. Likewise, the preference of (2R*,4r*,6S*)-2,6-dichloro-4-methyl-heptane (9) to populate the extended conformation mirrors that of the 2-chloro-4-methyl-heptane subunits. There is therefore no cooperative effect (neither positive nor negative) between the 2,4-disubstituted pentane subunits in determining the conformer preferences of the 2,4,6-trisubstituted heptanes studied. (C) Elsevier Science Ltd. All rights reserved.