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Studies On The Asymmetric Total Synthesis Of Natural Eudesmanes And Cadinenes

Posted on:2009-08-16Degree:MasterType:Thesis
Country:ChinaCandidate:F Q BiFull Text:PDF
GTID:2121360245481077Subject:Organic Chemistry
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This thesis aims at the studies on the asymmetric total synthesis of natural eudesmane and cadinene sesquiterpenes.It consists of the following four parts:Introduction Part:The background,intention and significance of the research of this thesis were introduced concisely.PartⅠ:The first asymmetric total synthesis of the enantiomers of natural 1β-hydroxy-eudesma-5,11-diene and 1β,11-dihydroxy-5-eudesmeneStarting from(+)-dihydrocarvone,using a substrate controlled hydromethylation to introduce the C-1 oxygenated group,a regioselective aldol reaction and a alkaline Robinson cyclization to assemble the decaIin skeleton,the first asymmetric total synthesis of the enantiomers of natural 1β-hydroxy-eudesma-5,11-diene and 1β,11-dihydroxy-5-eudesmene was accomplished.And the stereochemistry of the C-4 methyl group in natural 1β,11-dihydroxy-5-eudesmene was revised fromαtoβ.PartⅡ:The asymmetric total synthesis of cadinene sesquiterpenes.1.The basic configuration features and classes of cadinene sesquiterpenes were introduced concisely.2.The efficient synthesis of muurolane-type cadinenes was studied.Starting from R-(-)-carvone,using ring closing metathesis(RCM)reaction and allylic diazene rearrangement as the key steps,the first total synthesis of natural 10β-hydroxy-4-muurolen-3-one and the enantiomer of natural 10α-hydroxy-4-muurolen-3-one was accomplished.3.A highly efficient approach to the synthesis of the trans cadinane skeleton starting from R-(-)-carvone was developed.Using RCM reaction and a modified allylic diazene rearrangement as the key steps,the first asymmetric total synthesis of 4α,5α,10β-trihydroxycadinane and 4β,5α,10β-trihydroxycadinane was accomplished,the incorrect structural assignment of the natural cadinane made by Ahmed A.Mahmoud and et al.was revised and the absolute configuration of natural 4β,5α,10β-trihydroxycadinane was established.PartⅢ:ReviewIn this part,taking eudesmane-type and cadinene-type bicyclic sesquiterpenes for example,some published methods for construction of decalin ring system were reviewed.
Keywords/Search Tags:Asymmetric
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