Studies On The Total Synthesis Of (-)-Heliconol A, Kawain, Isochroman And Norlignans Compounds

This thesis main focused on the total syntheses of several natural products. Include thefollowing five parts:Chapter 1. The recent progress on the study of the Prins Cyclization (review)The review introduced some methods on recently study of the Prins Cyclization, and which were applied in the synthesis of natural products.Chapter 2. The first total synthesis of 7-butyl-6, 8-dihydroxy-3(R)-pentylisochroman -1-oneThe definition, classification of isochroman comounds, and previous synthetic reports of them were introduced briefly. A novel approach has been found and the first total synthesis of 7-butyl-6,8-dihydroxy-3(R)-pentylisochroman-l-one was accomplished. In which Sharpless asymmetric dihydroxylation was the key stepChapter 3. The first total synthesis of (-)-Heliconol A and its diastereoisomerThe definition of heliconol A compounds were introduced in brief. A facile total synthesis of the (-)-Heliconol A as well as its diastereoisomer is described, in which different reaction sequences lead to different results. If osmylation followed hydrolysis afforded a single isomer, otherwise, afforded a mixture of (-)-Heliconol A and its diastereoisomer 3-18. Other important processes include the catalytic asymmetric CBS reduction and induced highly stereoselective osmylation.Chapter 4. Enantioselective synthesis of all stereoisomers of Dihydrokawain and Dihydrokawain-5-olThe activity of Dihydrokawain and Dihydrokawain-5-ol were introduced and previous synthetic reports of them were introduced in brief. The enantioselective synthesis of all stereoisomers of Dihydrokawain and Dihydrokawain-5-ol was shortly achieved from readily available allenylboronic esters, in which condensations of aldehydes with chiral allenylboronic esters as the key step.Chapter 5. A facile approach to synthesis of the di-O-methyl ethers of (-)-agatharesinol, (-)-sugiresinol, (+)-nyasol and (+)-tetrahydronyasolThe activity of (-)-agatharesinol, (-)-sugiresinol were introduced and previous synthetic reports of them were introduced in brief. The facile enantioselective synthesis of the di-O-methyl ethers of (-)-agatharesinol, (-)-sugiresionl, (+)-nyasol and (+)-tetrahydronyasol were achieved in high yield. The absolute configuration of (+)-nyasol was confirmed via first total synthesis of (+)-nyasol and (+)-tetrahydronyasol.