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Efficient Activation of 2‐Iminomethylpyridine/Cobalt‐Based Alkyne [2+2+2] Cycloaddition Catalyst by Addition of a Silver Salt
Author(s) -
Goswami Avijit,
Ito Taichi,
Okamoto Sentaro
Publication year - 2007
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200700188
Subject(s) - chemistry , alkyne , cobalt , catalysis , trifluoromethanesulfonate , cationic polymerization , substrate (aquarium) , cycloaddition , zinc , ligand (biochemistry) , salt (chemistry) , chloride , medicinal chemistry , polymer chemistry , inorganic chemistry , organic chemistry , biochemistry , oceanography , receptor , geology
The addition of silver triflate (AgOTf) or silver hexafluoroantimonate (AgSbF 6 ) significantly increased the activity of the 2‐(arylimino)methylpyridine/cobalt(II) chloride hexahydrate (CoCl 2 ⋅6 H 2 O)/zinc catalyst in alkyne cyclotrimerizations thereby accelerating the reaction and enabling the use of unactivated, simple internal alkynes as the monoyne substrate: The rate of reaction was found to be highly dependent on the nature of the counter anion (X − ) and the ligand (L) in the postulated cationic cobalt(I) complex [LCo(I)] + X − .