Studies On The C(O)C-C Bond Insertion Of Carbonyl Compounds Towards Butadienol Derivatives And Subsequent Reactions

The insertion reaction of C-C bonds can efficiently and directly reorganize the molecular framework with high atomic efficiency,which is in line with the pursuit of green chemistry.The development of novel methodologies for the transition-metal-free C-C bond insertion reaction with simple and readily available starting materials is an attractive subject of research activity.In recent years,our group has developed mild and transition metal-free C(O)C-C bond insertion reactions of carbonyl compounds.These novel C-C bond insertion reactions can efficiently construct a series of polysubstituted butadienol derivatives.However,we are currently faced with a new challenge of developing new reaction reagents to develop novel reaction modes.At the same time,the butadienol structure has multi-reactive sites,but there are few reports on its synthesis,especially the synthesis of polysubstituted butadienol derivatives.Based on these,this thesis first developed a new C-C bond insertion reagent,and realized the novel 1,2-difunctionalization of alkynones with the same polarity by means of the umpolung strategy.Secondly,based on the structural characteristics of the multi-reactive sites of butadienol structure,we have carried out a series of subsequent reactions studies of C-C bond insertion reaction products by combining different reaction modes such as cycloaddition reaction or coupling reaction,and synthesized a variety of complex fused ring compounds.And in the course of these studies,we developed a novel indole C2-N1 ring expansion reaction.It mainly includes the following four parts:1)We developed the novel reagents,α,α-dithioketones,and achieved1,2-difunctionalization of alkynones with the same polarity via base-promoted C-C bond insertion reaction.This reaction utilizes 1,3-dithiane as the acyl protecting group to achieve polarity reversal.In this reaction,carbonyl group and 1,3-dithiane are simultaneously introduced to both sides of the triple bond through a base-promoted C-C bond insertion reaction,followed by the silver-catalyzed deprotection process to successfully achieve carbonyl-esterification of alkynes,resulting in the synthesis of the cyclic tetrasubstituted alkene,γ-hydroxybutenolide derivatives.This strategy provides an alternative research idea for the bifunctionalization of alkynes with the same polarity.2)We synthesized cycloheptadienol derivatives by the C-C bond insertion reaction of cyclic carbonyl compounds,and then cascaded the subsequent intermolecular cyclization and hydroxyl migration process to directly and efficiently synthesize 21 kinds of tricyclic oxaheteroaromatics containing mid-ring and pyran skeleton in one pot.This method greatly simplifies the synthesis steps of the fused ring compound fused with the middle ring and the pyran skeleton,has high atom economy,does not require the participation of transition metals,and has the other advantages of high atom economy,without transition metals,mild reaction conditions,and operational simplicity.3)Subsequently,we synthesized a series of butadienol derivatives containing indole structures by the C-C bond insertion reactions of indole 2-substituted alkynones,and then combined with subsequent coupling reactions to selectively synthesize cyano-substituted carbazoles and pyrano[2,3-b]indolones compounds.The synthesis process of cyano carbazoles derivatives first undergoes the base-promoted C-C bond insertion reaction of indolyl alkynones to produce a series of butadienol derivatives containing indole structures.Subsequently,under the catalysis of Fe(Ⅱ),the C-H/C-H coupling and acyl transfer process were realized with the help of enol tautomerism,and finally,23 kinds of cyano-substituted carbazole derivatives were synthesized.On this basis,we adjusted reaction conditions and chemoselectively synthesized 16 kinds of polysubstituted pyrano[2,3-b]indolones via iodine-promoted C-H/O-H coupling and acyl migration progress.This synthetic strategy effectively connects the C-C bond insertion reaction with the coupling reaction,which provides an efficient and convenient synthetic route for the synthesis of complex molecules.4)Based on the above studies,we developed a novel Br(?)nsted acid-promoted selective C2-N1 ring-expansion reaction of indoles using butadienol derivatives containing indole structures as raw materials,which produced 18 kinds of cyclopenta[b]quinoline derivatives in excellent yields(85-99%).By adjusting the reaction conditions,we also selectively synthesized 12 kinds of C2-spiroindoline derivatives in excellent yields(83-99%).The mechanism studies shown that the reaction may involve the process of dearomatising spirocyclization of indole and the subsequent migration rearrangement of the C2-spiroindoline.Besides,the acidity of the reaction system plays a crucial role in the process of spirocyclization and migration rearrangement.This reaction is the first selective C2-N1 ring-expansion reaction of indoles achieved by migration rearrangement of spiro derivatives.