The Total Synthesis And Absolute Configuration Of The Long Chain Alkylene Triols. Avocado Persea Americana Contained Determined

This thesis describes a synthetic study directed towards establishment of the stereochemistry of a natural (E)-nonadec-6-ene-1,2,4-triol isolated by Fumiko et al. from the seeds of Persea Americana. Although the original authors managed to elucidate the planar structure of this compound, the small quantity of the natural sample made it impossible for them to assign the relative as well as absolute configurations.The synthesis was achieved using a chiron approach, with the inexpersive and readily available glucolactone of high optical purity as the source of the chiral centers. The starting carbohydrate was first converted into two enantiopure epoxy chiral building blocks containing hidden syn and anti 1,3-diol motif, respectively, and than further elaborated into the end products via opening the epoxy ring with a terminal alkyne, alkaline metal reduction in liquid ammonia, hydrolytic removal of the acetonide protecting group, removal of the surplus chiral center/carbon by oxidative cleavage, and reduction of the newly formed terminal aldehyde group to give the desired target (E)-alkene-triol.Data comparison between the synthetic and the natural samples unequivocally shows that the natural product must have a (2R,4R) configuration and thus complete the whole structural assignment.