The Applications Of (E)-β-Arylselenenylviny-zirconium Complexes In Highly Selective Synthetic Reactions

Part one :We describe the synthesis of (E)-1-arylseleno-2-arylsulfanylet-henes and their applications as 1,2-difunctional reagents in highly selective synthetic react- ions.(Trimethylsilyl)acethylenic Grignard reagents reacted with arylselenenyl bromides to give 1-(trimethylsilyl)-2-arylselenoethynes,which were treated with potassium fluoride in methanol affording a new approach to synthesis of arylselenoethynes. (E)-1-Arylseleno-2-arylsulfanylethenes could be conveniently synthesized by hydrozirconation of arylselenoethynes, followed by reacting with arylsufenyl chlorides. (E)-1-Arylseleno-2-arylsulfanylethenes underwent the cross-coupling reaction with Grignard reagents in the presence of the NiCl₂(dpp)₂ catalyst stereoselectively to give (E)-1,2-disubstituted alkenes.Part two:The hydrozirconation of arylselenoethynes with Cp₂Zr(H)Cl gave (E)-β-arylselenovinylzirconium complexes,which were treated with iodine affording a general approach to synthesis of (E)-β-iodovinylselenides. (E)-β-Iodovinylselenides underwent cross-coupling reactions with terminal alkynes in the presence of Pd(PPh₃)₄/CuI, providing a new method to synthesize stereoselectively (E)-1,3-enynylselenides. (E)-1,3-enynylselenides can undergo NiCl₂(PPh₃)₂-catalyzed cross-coupling reactions with alkynyl Grignard reagents, providing a convenient approach to the stereoselective synthesis of (E)-1-enediynes. (E)-1-arylselenenyl-1-buten-3-ynes were prepared by the desilylation reactionof (E)-1-arylselenenyl-4-(trimethylsilyl)-1-buten-3-ynes with potassium fluoride. We found that (E)-1-arylselenenyl-1-buten-3-ynes reacted with vinyl iodides in the presence of Pd(PPh₃)₄/CuI. providing a new route to the stereoselectivesynthesis of 1-arylselenenyl substituted (1E,5E)-dienyne...