Synthesis Of Wikstrol A/B And Morelloflavone

Biflavonoids are low molecular weight polyphenol natural compounds.They belong to a kind of flavonoids which are mostly found in gymnosperms and pteridophytes.Both Wikstrol A and B and Morelloflavone belong to 3,8"-type biflavonoids.Wikstrol A and B belong to flavanol-type biflavonoids and morello flavone belongs to dihydroflavonoid biflavonoids.Previous research showed that Wikstrol A had good anti-inflammatory activity and inhibited aldose reductase.Morelloflavone has been used in China as drugs for a long time.Modern research found that it has good anti-tumor activity.However,the synthesis of these three biflavonoids has not been reported.In this thesis,we designed a route to synthesize Wikstrol A and B using rhodium catalyzed oxidative coupling as key step based on our previous synthesis of 3,8"-type biflavones 13,118-biapigenin and Ridiculuflavone A.The total synthesis of Wikstrol A and B was achieved from 2’,4’,6’-trihydroxyacetophenone by selective protection of phenol,aldol reaction,reduction reaction,Sharpless asymmetric dihydroxylation and cyclization reaction under acidic conditions,regio-selective iodination reaction,Sonogashira reaction,rhodium catalyzed oxidative coupling and deprotection reaction.Moreover,we tried to improve the yield of the key reaction by changing the protective group and found the protection group did not affect much on the yield.Then we attempted to synthesize Morelloflavone target molecule using cobalt-catalyzed oxidative coupling reaction and TMSOTf-promoted cyclization reaction as key reactions.However,no desired product was obtained.The structures for all new compounds were confirmed by 1H-NMR,13C-NMR,and HRMS;Moreover,the structure of fully protected Wikstrol A was further confirmed by single crystal X-ray analysis.