Study On The Rearrangement-cyclization Reaction And Fluorination Reaction Of ?-diazo Imine

1,2,3-triazoles are important heterocyclic compounds with biological activities,which can be transformed into metal-carbene under the catalysis of transition metals.The latter can be used as a kind of very important active intermediates for a series of transformation reactions,which play a very important role in organic synthesis.In recent years,rhodium-catalyzed N-sulfonyl-1,2,3-triazoles has been associated with a large number of reports on the reaction of?-imino rhodium carbenoid intermediates.For example,X-H?C-H,O-H and N-H?insertion reactions,cyclopropane,ylide formation,1,2-migration,coupling reaction and so on.In addition,except for rhodium,other transition metals?such as nickel,palladium,copper,silver,etc.?can also catalyze or promote the reaction of 1,2,3-triazoles.Such strategy has been employed widely in efficient synthesis for various heterocyclic compounds bearing novel structures and potentially valuable functionalities.This thesis mainly studied the rhodium catalyzed synthesis of 1,2-dihydropyridine compounds and metal-free Et₂O·BF₃participatedsynthesisof?E?-monofluoroenaminesfrom N-sulfonyl-1,2,3-triazoles.?1?Rhodium-catalyzed synthesis of 1,2-dihydropyridine was achieved via a tandem reaction of 4-?1-acetoxyallyl?-1-sulfonyl-1,2,3-triazole including formation of a-imino rhodium carbene,1,2-migration of an acetoxy group and six electron electrocyclic ring closure.Under nitrogen atmosphere,when 4-?1-acetoxyallyl?-1-sulfonyl-1,2,3-triazole was treated with 3 mol%of Rh₂?adc?₄ in toluene at 50 ^oC,1,2-dihydropyridine compounds could be obtained in moderate to good yields.The readily accessing to the substrates,the mild reaction conditions and the versatility of the dihydropyridines should enhance the synthetic potential of this transformation.?2?Metal-free and Et₂O·BF₃ promoted synthesis of?E?-monofluoroenamine from N?Sulfonyl-1,2,3-triazole via stereospecific fluorination of??diazoimine was realized.Under nitrogen atmosphere,when N-sulfonyl-1,2,3-triazole and 1.5 equiv Et₂O·BF₃were treated with 0.2 equiv TBAF.3H₂O as additive in 1,2-DCE at reflux,?E?-monofluoroenamine compounds could be obtained stereospecifically in up to 85%yield.This is the first Lewis acid promoted ring-opening reaction of N-sulfonyl-1,2,3-triazole.