The Synthesis Of Natural Product Gingerdiol And Its Epimer

This M.S. degree thesis concentrates on the preparation of chiral epoxy building blocks which are the precursor of the intermediates of natural products and the stereospecific synthesis of natural product Gingerdiol. Furthermore, we also accomplished the stereospecific synthesis of the epimer of natural product and reported its related data for the first time. Meanwhile, during the synthesis, we found some by-products in CM reaction which the substrate is unprotected5-substituted pent-1-ene-3,5-diols. We put up the mechanism of the CM reaction through a series of explorations and experiments. Finally, we promoted the yield of target coupling product through changing the reaction process and optimizing the reaction conditions,In the first part of this work, we use the cheap and readily accessible D-glucolactone to get the epoxy chiral building blocks without chromatographing, through very easy post-processing and recrystallization. What’s more, the scale can increase to10g level and the productivity is very stable.In the second part of this work, both (3R,5S)-and (3R,5R)-gingerdiols were synthesized. Their1,3-diol motifs were derived from enantiopure epoxy chiral building blocks.What’s more, the natural products the configuration is (3R,5S)-gingerdiol which we certified finally. In addition, the effect of deuterating the OH groups of the natural isomer on its optical rotation was also examined.In the third part of this work, the reaction mechanism and the control of reaction process Cross-Metathesis reaction of unprotected5-substituted pent-1-ene-3,5-diols was investigated. The results proves that the CM product readily underwent an allylic epimerization and oxidation, as the starting diols rearranged into ketones with unprecedented ease. In reaction to the phenomenon, we put forward the rational mechanism of the generating of CM products through a series of explorations and experiments. We made the yield of target cross-coupling product increase from24%to63%through using the toluene as the solvent and adding the phenol to the system.