Construction Of Quaternary Carbon Centers Catalyzed By Ni And Fe

The thesis focuses on the construction of quaternary carbon centers by transition metal nickel catalyzed reduction coupling,including nickel catalyzed reductive allylation of tertiary alkyl halides with allylic carbonates,and nickel catalyzed arylation of tertiary alkyl oxalates with aromatic halides.In addition,this thesis will also introduce the iron promoted allylation of tertiary alkyl oxalates with allylic carbonates.1.With zinc as reductant,we have successfully developed the nickel catalyzed reductive allylation of tertiary halides with allylic carbonates.This strategy features mild reaction conditions,excellent substrate scope,good regioselectivity.No isomerization of tertiary alkyl groups was observed which is often found in arylation and acylation of the tertiary electrophiles.With this strategy,a series of allylated C(sp~3)-quaternary carbon centers have been successfully constructed.2.With zinc as reductant,we have successfully advanced the nickel catalyzed reductive arylation of tertiary alkyl oxalates with aromatic halides.The strategy arose from cleavage of the unactivated Barton type tertiary alkyl C-O bonds to generate the tertiary alkyl radical under mild conditions.Good substrate scope for the tertiary alkyl oxalates and electron-withdrawing aromatic halides were observed.With this strategy,a series of arylated quaternary carbon centers have been successfully constructed.3.With iron as promoter or catalyst,zinc as reductant,and magnesium chloride as additive,we have successfully developed the reductive allylation of tertiary alkyl oxalates with allylic carbonates that generates all C(sp~3)-quaternary carbon centers under mild reaction conditions.By introduction of activated alkenes,a three-component radical cascade reaction took place.With this strategy,a series of allylated C(sp~3)-quaternary carbon centers and three-component cascade radical addition products contain quaternary carbon centers have been successfully constructed.