No abstract

No abstract

No abstract

Sztrnmary.A brief synthesis of damascenone (5) from the acetylenic diol 2 and also that of /?-damascone (8) from p-ionol, resembling the biogenetic synthcsis, are described. A possiblc mechanism for the formation of damascenonc from neoxanthin is proposed.In recent years the isolation of daniascenone (5) and P-damascone (8) [lj from several plants has stimulated considerable interest because of their powerful and pleasant fragrance. Our own interest in this field has been concerned with the metabolism of carotenoids [a].We report herein a brief synthesis2) arid a possible hiogenesis of damascenonc and ~-darnascoiie.Reaction of the ketone 1 (derived from 2,2,6-trimethylcyclol~exanone by bromination followed by dehydrobromination with dimethyl sulfoxide in the presence of sodium hydrogen carbonate [4]) with the lithium derivative of but-3-yn-2-01 in liquid ammonia yielded the diol 2, m.p.Summary. The literature data on hcteropolar and homopolar 2-center bond dissociation energies in organic molecules in the gas phase and the corrcsponding heats of formation of radicals and ions havc been critically evaluated. Data for more than 500 bonds are represented in tabular form together with the pertinent literature references.Selected electron affinitics and n-bond dissociation energies have also bccn incorporated. The follow-up paper will discuss some cmpirical general aspects of these data particularly regarding the effect of structure on the bond dissociation energies.

No abstract