Preparation and conformational analysis of severely hindered β-diketones. Dipole moment determinations and theoretical calculations.

Abstract

Several β-diketones bearing bulky substituents at the intercarbonyl positions have been prepared by alkylation of the cobalt(II) complexes of the unsubstituted diketones. Agreement between experimental and calculated dipole moments is fairly good thus rendering Molecular Mechanics a safe tool for the conformational analysis of the title molecules. The most populated conformations have been evaluated for nine ϱ-diketones bearing 1- and 2- adamantyl, tert-butyl, cyclohexyl, 1-phenylethyl and benzhydryl groups as well as two methyl groups and one methyl plus one 1-adamantyl groups.