Several Hydroxyl Group-containing Chiral Centers Natural Small Molecule Synthesis And Structure Type Determined

The natural product7-Phenylhepta-4,6-diyne-1,2-diol the proposed structures forSchweinfurthinol have been totally synthesized.The first part of this thesis deals with the synthesis of7-Phenylhepta-4,6-diyne-1,2-diol, a natural butanolide produced by Lanzhou Institute of Chemical Physicsisolated from Bidens pilosa (family Asteraceae). The whole synthesis consists of6steps of reaction, Benzyl (S)–(+)–Glycidyl Ether featuring a ring-opening of anoptically-active epoxide with a Trimethylsilylacetylene in the presence of n-BuLi,coupling reaction as the key steps.The second part of this thesis describes the total synthesis of the structuresproposed for Schweinfurthinol, which were isolated by Tamboue Helene from C.schweinfurthii.(R)-glyceral acetonide, a chiral building block readily prepared fromD-mannitol, with a4-Bromophenol in the presence of n-BuLi. Then the chemicalcompound synthesized via oxidizing and deprotection. An acid-mediated ring-closurefollowed by decarboxylation established the γ-lactone unit. Analogues of differentrelative configurations were also synthesized. In summary, the structures proposed inthe literature for the natural Schweinfurthinol have been synthesized for the first timethrough an efficient and enantioselective route. However, the disagreement betweenthe [] data still remained. Unexpectedly, the [] data of the synthetic samples werenot in full consisitence with those reported for the natural Schweinfurthinol. Thesynthetic samples helped to reveal some erroneous in the [] data given in theliterature by HPLC.