Marmelo oxides

The reaction was applied to an acyclic system for the synthesis of furanoid terpenes (Scheme ll)51. The palladium-catalyzed intramolecular reaction of 47 afforded 48 which was transformed to the target molecule. The latter product was obtained as a 1 1 mixture of marmelo oxide A and B, which is the isomeric mixture found in nature. 

In the case of the C]j-isoprenoids, it is noteworthy that attractive aroma compoimds were foimd to be derived from the central part of the carotenoid chain which remains after the cleavage of the C j-endgroup. Examples are the key flavor compoimds of quince fruit, i.e. marmelo oxides and marmelo lactones (76). 

Synthetic Applications In several syntheses toward naturally occurring furanoid terpenes, the intramolecular oxyacetoxylation was applied as a key step [125]. For example, in the synthesis of marmelo oxides A and B,... 

The decision of what should be placed in this section is not obvious. Actually all monoterpenoid furan derivatives could be classed as oxygenated dimethyloctanes, but so could most other monoterpenoids, and it is to lessen the load in other sections that we include this one. We should point out that we have already discussed eldanolide, menthofurans, marmelo lactones, and oxides, and the 7-hydroxygeranic acid derivatives, cleveolide and scobinolide. 

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