ChemInform Abstract: The Effect of Phenyl Groups on the Homoconjugation in the Bicyclo[3.2.1]octa-3,6-dien-2-yl Anion.
Abstract
The effects of deuterium atoms in the 2 and 4 positions of the compounds (Ia), (Ib), and (II) on their ′3C chemical shifts are in line with the previous interpretation of the effects in correspondingly deuterated anions (III), and thus provide evidence for homoconjugative interaction in (III).
ChemInform Abstract
The effects of deuterium atoms in the 2 and 4 positions of the compounds (Ia), (Ib), and (II) on their ′3C chemical shifts are in line with the previous interpretation of the effects in correspondingly deuterated anions (III), and thus provide evidence for homoconjugative interaction in (III). The investigated anions (V), (VI), (VII) and (IX) are prepared from their corresponding precursors (IV) or (VIII) as shown in the scheme. The hitherto unknown precursors (IVa) and (IVc) + (IVd) (mixture) have been prepared Starting from the Carbonyl compounds (X) and (XIII), respectively. - The ′3C NMR spectra of the anions (V)-(VII), (IX) and of the corresponding hydrocarbons (IV), (VIII) are discussed in detail in relation to the spectra of the unsubstituted species (III) and (XVI). In particular, the wide variations of the chemical shifts of C-6,7 depending upon the substituents of the allylic moiety of the title anion system give strong support for the bishomoaromatic nature of these anions.
