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Versatile Pd‐Catalyzed CH Oxidative Cyclization of Homoallylhydrazones to Pyrazolines and Tetrahydropyridazines
Author(s) -
Mboyi Cleve Dionel,
Abdellah Ibrahim,
Duhayon Carine,
Canac Yves,
Chauvin Remi
Publication year - 2013
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300220
Subject(s) - catalysis , ligand (biochemistry) , chemistry , imidazole , ionic bonding , medicinal chemistry , oxidative phosphorylation , salt (chemistry) , palladium , oxidative addition , stereochemistry , ion , organic chemistry , receptor , biochemistry
Pd‐catalyzed 5‐ exo ‐ trig or 6‐ endo ‐ trig CH oxidative cyclization of C ‐homoallyl‐ N ‐sulfonylhydrazones to 5‐vinylpyrazolines or 6‐methylidene‐1,4,5,6‐tetrahydropyridazines, respectively, is shown to be controlled in a highly selective manner by the ionic character of the Pd II catalytic center. This character is ultimately defined by the nature of the X ligand in the PdX 2 salt serving as an in situ precursor of the active catalytic species involving BIPHIMIP {2‐(diphenylphosphino)‐1‐[2‐(diphenylphosphino)phenyl]‐1 H ‐imidazole} as an optimal spectator diphosphine ligand for both processes. Whereas acetates (X=OAc) favor the 6‐ endo process, noncoordinating anions such as tosylates and triflates (X=OTs, OTf) favor the 5‐ exo process.