Studies On The Bifunctionalization Of Alkynes

Alkynes and their derivatives are widely found in nature and play an important role in organic synthetic chemistry as a basic raw material.The bifunctionalization of alkynes is one of the main methods for regioselective organic synthesis of trisubstituted/tetrasubstituted olefins.With the development of transition metal catalytic reaction methodology,it is now possible to construct the polysubstituted olefins containing C-C/C-X bonds with higher yields.However,most transition metal catalysts are relatively expensive,Which limits their industrial applications.In recent years,people have become more and more aware of the importance of protecting the environment.The research on the bifunctionalization of alkyne without metal participation has become more and more popular among chemists.The bifunctionalization of alkynes has evolved into an easy,efficient,and highly atom-economic method for the simultaneous introduction of various functional groups on carbon-carbon triple bonds.Based on the previous studies,I have carried out some research on the bifunctionalization of alkynes.This thesis is mainly divided into the following parts:1.The self-coupling reaction of haloalkynes in the presence of NHC-Au?I?was studied.The reaction successfully realized the self-coupling reaction of haloalkynes by using haloalkynes as easily available starting materials and NHC-Au?I?as catalyst.A variety of gem-halolefins which can serve as an important class of synthetic raw materials and intermediates could be synthesized in moderate yields.2.The Cu?0?/Selectfluor system-catalyzed intramolecular tandem cyclization of aryldiynes was studied.The reaction was initiated by the combination of a small amount of inexpensive metallic copper powder and Selectfluor to form an intermediate active species-XCuOH?X=F or BF₄?,Which underwent oxycupration reactions toward the carbon-carbon multiple bonds.The indenone derivatives were synthesized in a moderate to good yields.3.The I₂O₅/H₂O system-promoted 1,5 cyclization of aryldiynes was studied.The3-acyl-1-indenone derivatives were synthesized in a moderate to good yields by using water as a solvent and an oxygen source.The reaction has advantages of a metal-free process,mild reaction conditions,simple operation,and broad functional group tolerance.