Circular Dichroic Studies on Marmelo Lactones and the Related γ-Lactones with Unsaturation at the C-5 Position

抄録

The intense CD bands of marmelo lactones and the related γ-lactones with unsaturation at the C-5 position were studied in terms of the possible interactions between the n→π^* transition of the carbonyl and the π→π^* transition of the double bond at C-5, together with the preferred conformations about the C4-C5 axis. The C4-C5 axis of marmelo lactones takes a preferred conformation which is characteristic for the acyclic allylic alcohols and seems to be an important factor for the (4S)-γ-lactones with a double bond at the C-5 position to give a negative coupling between the two chromophores.