Research Of Nickel-catalyzed New Type Reactions Of α-hydroxycyclobutenones And Biomimetic Synthesis Of Diquinone Natural Products,Parvistemin A And (±)-Diperezone

This dissertation had finished correlation studies ofα-hydroxycyclobutenones in two aspects of organic synthetic methodology and total synthesis of natural products.The first part:nickel-catalyzed ring-opening ofα-hydroxycyclobutenones with“donor-inward”torquoselectivity and remarkable ligand effect.Benefiting from its particular four-member ring skeleton structure,α-hydroxycyclobutenones have the high chemical activity which could trigger a variety of transformations under different conditions,such as four electronic ring-opening/6π-electrocyclization,[2+2]cycloaddition,carbonyl-ene reaction,[4+2]cycloaddition,[4+1]annulation etc.Among them,the methods using transition metal catalyzedα-hydroxycyclobutenones’ring opening obtained attentions in the field of organic chemistry.In this chapter,firstly,we summarized the development history of transition metal complexes such as ruthenium,rhodium,cobalt as well as nickel which catalyzed the ring-opening andexpanding reactionsofα-hydroxycyclobutenones.Then we presented the two interesting torqueselectivity,“donor-outward”and“donor-inward”,which could induce numerous conversions in the ring-opening ofα-hydroxycyclobutenones.We used catalytic amount of Ni（cod）₂ and ligand to promote the ring-opening ofα-hydroxycyclobutenones whose torqueselectivity is“donor-inward”.Then we filtered the reaction conditions and find that ligand effect could be observed to control the process after the ring-opening.The employment of different ligand leads to the formation of different 2-furanones respectively.Our above-mentioned discovery is the first example of transitional metal catalyzed electrocyclic ring-opening reactions ofα-hydroxycyclobutenones with“donor-inward”torquoselectivity.The second part:biomimetic synthesis research to natural products as parvistemin A,（±）-diperezone and perezoperezone.In this chapter,we summarized some synthetic strategy of diquinone natural products in recent years.And we projected an concise biomimetic synthesis strategy of the diquinone.The strategy’skeybasedontwothings.Oneisthefourelectronic ring-opening/6π-electrocyclization ofα-hydroxycyclobutenones.And the other is the oxidative coupling of phenol compounds.In the process of our exploration,we discovered that 1,2,4-trihydroxy phenol could transform into diquinone by oxidative coupling or dimerization in high yield.This method was taken as the key step to accomplish the biomimetic synthesis of parvistemin A and（±）-diperezone efficiently.Afterwards,（±）-perezone was worked as the precursor in the conversion of perezoperezone.We tried our best to the synthesis of the complicated natural product perezoperezone.