Some New Organic Reactions Of Alkynes And Allenes

This dissertion mainly describes several organic reactions of alkynes and allenes,including Cu-catalyzed Sonogashira cross-coupling reaction,plladium-catalyzed cyclization of N-arylpropiolamides with arynes,and electrophilic cyclization of allenes.The main contents are as followed.1.The Cu₂O/PPh₃/TBAB catalytic system was found to be efficient for the Sonogashira cross-coupling reaction.In the presence of the octahedral Cu₂O nanoparticles,PPh₃,and TBAB,a variety of aryl and heteroaryl halides reacted with alkynes smoothly in 10%to 98%yields. Noteworthy is that the system can be recovered and reused several times without loss of activities.2.Palladium-catalyzed cyclization of N-arylpropiolamides with arynes has been described.In the presence of Pd(dba)₂,a variety of N-arylpropiolamides underwent the reaction with arynes to afford the corresponding 3-(1-arylmethylene)oxindoles in 6%to 66%yields.3.A selective method for the synthesis of 3-iodofurans via electrophilic cyclization of allenyl ketones with N-iodosuccinimide in MeCN has been developed.In the presence of NIS,3-iodofurans were selectively prepared from the electrophilic cyclization of allenyl ketones in 31%to 78%yields.