Study On The Reaction Of Vinyl Azides With Sodium Arylsulfinates

Vinyl azides,molecules that feature both alkene and azide motifs have been known for around a century.In recent years,vinyl azide compounds have attracted more and more attention,and have been studied as important organic synthesis intermediates.Due to the distinctive structure of vinyl azides,they show many unique reactivities of azido and alkene groups.Vinyl azides can act as radical acceptors,nucleophile reagents or electrophile reagents in organic reactions.Simultaneously,they can also form important organic synthesis intermediates,such as 2H-azirines,metal enaminyl radicals,imino radicals,etc.,to further transform into a series of nitrogen-containing heterocyclics,amides,amines and other nitrogen-containing organic compounds.Based on the unique reactivity of vinyl azides,we developed the study of the reaction of vinyl azides and sodium arylsulfinates.The thesis is divided into four chapters.Chapter 1.Application of vinyl azides in organic synthesisThe preparation and applications of vinyl azides in organic synthesis was reviewed in detail in this chapter.Vinyl azides can act as radical acceptors,nucleophiles,and electrophiles in different reactions and have attracted more focuses of chemists and show more important role in organic synthesis.Based on the review,the investigation on the reaction of vinyl azide and sodium arylsulfinates was developed.Chapter 2.Iodine-catalyzed synthesis of?-sulfonyl enamines from vinyl azides and sodium arylsulfinatesN-Unprotected?-sulfonyl enamines are useful organic synthesis intermediates.Using vinyl azides and sodium arylsulfinates as raw materials,iodine-catalyzed the synthesis of N-unprotected?-sulfonyl enamines was studied.The reaction was conducted in ethanol at 40°C for 4-6 h with 10 mol%of iodine as a catalyst and 0.5equivalent of Tf₂NH as a cocatalyst.22?-sulfonyl enamines were obtained in the yield of 49%-81%with 100%Z-form selectivity.This method shows some advantages,such as transition metal-free,simple and mild reaction conditions,short reaction time,good product yield and high stereoselectivity.Chapter 3.Cu-promoted synthesis of?-carbonylsulfone from the reaction of vinyl azides and sodium arylsulfinates?-Carbonylsulfone motif is a very important building block in organic synthesis and pharmaceutical synthesis,which shows some bioactivities.In this work,the synthesis of?-carbonylsulfones from the reaction of vinyl azides and sodium arylsulfinates under acidic conditions was explored.The reaction was accomplished by using two equivalents of Cu?OTf?₂ as a Lewis acidic promotor in ethanol at 60°C for 4-6 hours and 27?-carbonylsulfone compounds were synthesized in up to 82%yield.A lot of substituents bearing on substrates show good tolerance.The method shows wide substrate scope,good substitutent tolerance,short reaction time,mild reaction conditions and simple operation.Chapter 4.Summary and perspectiveThe work in this thesis focused on the cross-coupling reaction of vinyl azides and sodium arylsulfinates under different reaction conditions.Iodine-catalyzed reaction was proceeded to access?Z?-?-sulfonyl enamines via free radical addition,whereas Cu?OTf?₂-promoted reaction resulted in?-carbonylsulfones via probable cation mechanism or free radical addition.The latter will be further studied in future work.All reactions yielded the target products in moderate to good yields.In perspective,vinyl azides as versatile reagents will be used in more and more organic reactions to form nitrogen-containing even some nitrogen-free compounds.We will further explore the application of vinyl azides in organic synthesis in order to establish new reactions and new methods about vinyl azides.