六環[6.6.2.23,6.210,13.02,7.09,14]二十-4,11,15,17,19-五烯分子架構系列之合成

• Main Authors: KunZe Chen, 陳昆澤
• Other Authors: Cheng-Tung Lin
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/51126842269963253516

碩士 === 東海大學 === 化學系 === 88 === Abstract Synthesis and characterization of a new hexacyclic hydrocarbon 13 is resported. The chemical shift of vinylic hydrogen absorptions are measured in order to examine the transannular orbital interaction between the parallel C=C double bonds. Diels-Alder reaction of tricyclic triene 1 with diethyl fumurate produced the cycloadduct 2a. Subsequent reduction , dechlorination and deacetalization afforded exocyclic 1,4-diol 5. Reaction of the corresponding diacetate 6 with p-benzoquinone in refluxing toluene resulted in slow decarbonylation , followed by cycloaddition to furnish a single cycloadduct 7. Reduction with sodium borohydride formed endiol 8 . Mesylation followed by elimination of the resulting 8 gave exocyclic cyclohexadiene 9. Diels-Alder reaction of 9 with diethyl fumurate produced a mixture of cycloadducts 10a and 10b. Subsequent reduction , bis-tosylation and elimination afforded 13. Alternatively Diels-Alder reaction of 9 with maleic anhydride produced the cycloadducts 14, followed by subsequent reduction, bis-tosylation and elimination to afford 13 . Dissolving metal reduction of 13 afforded 16 . Analysis of the nuclear magnetic resonance spectra verified the effect of homoconjugation . The center ethylene bridge is high field shift due to the shielding effect of the neighboring ethylene bridges . The linearly orthogonal C=C double bond , the fused exocyclic 1,3-butadiene , and benzene ring interact with the terminal ethylene bridge resulting in downfield shift of vinylic hydrogens.