Green Synthesis Of Functionalized N-Heterocycles Based On Homopropargyl Amides And Ynamides

N-heterocycle compounds have been verified to be very valuable compounds.N-heterocycle frameworks extensively exist in organic materials,natural products and small-molecule drugs.Therefore,the synthetic methodologies aiming at N-heterocycles are very essential.The dissertation starting from homopropargyl amides and ynamides two important synthons containing a nitrogen atom,develops green synthetic methodologies,such as photoredox-catalysis and metal-free catalysis leading to functionalized N-heterocycles.The contents of the dissertation are divided into four parts.The first part of the dissertation,introduced anti-Markovnikov reactions based on homopropargyl amides as well as radical reactions and asymmetric catalysis based on ynamides.Among these,regioselectivity of radical addition in the radical reactions of ynamides were discussed.In aspects of asymmetric catalysis of ynamides,we mainly reviewed asymmetric catalysis to synthesize N-heterocycles and listed asymmetric catalysis to construct axially chiral compounds.The second part of the dissertation,introduced the principle of photocatalytic organic reactions and gold/photocatalyst synergetic catalytic organic reactions.Based on these research,we developed twice gold/photocatalyst synergetic catalytic cycles based on homopropargyl amides to realize tri-functionalization of alkynes to construct bisarylative chiral dihydropyrroles.The third part of the dissertation,introduced photocatalyzed ketyl radical coupling reactions and radical Smiles rearrangement reactions.Based on research,we developed photocatalyzed ketyl-ynamide coupling initiating cascade reactions.Among these,intramolecular desulfonylated Smiles rearrangement was achieved to synthesize indoles and isoquinolines which are two valuable scaffolds.In addition,this rearrangement reactions could be extended to intermolecular ynamide Smiles rearrangement by addition of external radical sources.Notably,it’s the first example of ynamide Smiles rearrangement.Meanwhile,allyl alcohol transposition in one-pot allows to prepare useful 2-hydroxymethylindoles when the protecting group of ynamides is methylsulfonyl.In this part,four bioactive molecules could be obtained by simple derivatization of products.The fourth part of the dissertation,introduced synthetic methodologies to construct axially chiral indoles,among these,most reactions required noble-metal catalysis.However,metal-free catalyzed 5-endo-dig cyclization of ortho-alkynylaniline to construct more valuable N-arylindole compounds remain undeveloped.On the other hand,chiral Br?nsted acids catalyzed ynamides enables asymmetric catalysis.Inspired by these studies,we designed and realized Br?nsted acids catalyzed 5-endo-dig cyclization of ortho-ynamide anilines to construct axially chiral N-arylindoles.Moreover,we successfully synthesized thioureas and phosphines based on N-arylindole backbones,which are expected to be applicable to asymmetric catalysis.