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Cationic Nickel Complexes with Weakly Coordinating Counterions and Their Application in the Asymmetric Cycloisomerisation of 1,6‐Dienes
Author(s) -
Böing Christian,
Franciò Giancarlo,
Leitner Walter
Publication year - 2005
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.200505176
Subject(s) - chemistry , counterion , cationic polymerization , catalysis , nickel , medicinal chemistry , ligand (biochemistry) , stereochemistry , inorganic chemistry , ion , organic chemistry , biochemistry , receptor
The influence of the counterion on cationic nickel catalysts for asymmetric cycloisomerisation of diethyl diallylmalonate ( 1a ) and N , N ‐diallyltosylamide ( 1b ) is investigated. The activity of the catalysts formed from [Ni(η 3 ‐allyl)(η 4 ‐cod)] + salts of weakly coordinating anions in combination with Wilke's azaphospholene ligand decreases in the order [Al{OC(CF 3 ) 3 } 4 ] − >[B{3,5‐(CF 3 ) 2 ‐C 6 H 3 } 4 ] − >[Al{OC(CF 3 ) 2 Ph} 4 ] − for 1a and [B{3,5‐(CF 3 ) 2 ‐C 6 H 3 } 4 ] − > [Al{OC(CF 3 ) 2 Ph} 4 ] − >[Al{OC(CF 3 ) 3 } 4 ] − for 1b , respectively. No significant influence on the enantioselectivity is observed for 1a whereas a marked increase in ee parallel to a decreasing activity is found for the cyclisation of 1b .