| This thesis consists three chapters.The first part introduces the synthesis methods of 1,4-diketones and its application in organic synthesis.1,4-diketones are important intermediate to synthesis furan,pyrrole,thiophene and heterocyclic compounds.Many natural products consists the 1,4-diketone motif,so developing synthetic methods of 1,4-diketone compound are important in organic synthetic methodologies.The second part introduces a new synthetic method using metal Sm promoted reductive coupling reaction of halogenated ketone to synthesis 1,4-diketones including non-substituted 1,4-diketones and 2,3-disubstituted 1,4-diketones in high yields.The reaction conditions are simple and easy to operate with wide substrates adaptability.The third part introduces the synthesis of chamaejasmine.In 2005,Dr.Ma Baochun first completed total synthesis of racemic chamaejasmine.Our team continues to study the asymmetric total synthesis of optically active chamaejasmine.Optically active chamaejasmine containing four adjacent chiral centers,C2*,C3*,C2,C3,one C2 chiral axis,the entire molecules appears symmetry state.To solve the problem of the synthesis of optically active chamaejasmine,we must first complete the synthesis of chiral flavanone.Our group,Master Huang Jinbiao using the method of small molecule catalyzed that used thiourea compounds derived from quinine as chiral catalyst to synthesis the chiral flavanones,followed by metal promote reductive coupling reaction of halogenated ketone,first completed asymmetric synthesis of 3,3"-biflavanones,ee=92%.After completing asymmetric synthesis of 3,3"-biflavanones,we also used thiourea compounds as chiral catalyst to synthesis the 5,7,4 '-trimethoxy chiral flavanones.Followed by metal Sm promote reductive coupling reaction of a-iodo ketones,optically active hexamethoxy chamaejasmine was first completed witn 88%ee,and deprotection of six methlyether will give opitically active natural product chamaejasmine. |
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