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Allyl Palladium Complexes of Cycloheptatrienyl‐Cyclopentadienyl Phosphane Ligands in Buchwald‐Hartwig Amination Reactions
Author(s) -
Tröndle Sabrina,
Freytag Matthias,
Jones Peter G.,
Tamm Matthias
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900225
Subject(s) - chemistry , morpholine , palladium , amination , medicinal chemistry , catalysis , cyclopentadienyl complex , ligand (biochemistry) , aryl , ring (chemistry) , chloride , stereochemistry , organic chemistry , receptor , biochemistry , alkyl
A series of well‐defined palladium allyl chloride pre‐catalysts was synthesized using previously reported troticenyl phosphane ligands [(η 7 ‐C 7 H 7 )Ti(η 5 ‐C 5 H 4 PR 2 )] and [(η 7 ‐C 7 H 6 PR 2 )Ti(η 5 ‐C 5 H 5 )] (R = Cy, t Bu) as ancillary ligands. The formation of a dimeric µ‐chloro‐, µ‐allyl‐bridged Pd I species was observed with the ligand [(η 7 ‐C 7 H 7 )Ti(η 5 ‐C 5 H 4 P t Bu 2 )], whereas L 2 Pd 0 {L = [(η 7 ‐C 7 H 6 P t Bu 2 )Ti(η 5 ‐C 5 H 5 )]} was formed in presence of KO t Pent. In addition, the catalytic activity of the palladium allyl chloride pre‐catalysts was investigated in Buchwald‐Hartwig amination reactions with various aryl halogenides and N ‐methylaniline or morpholine. The cyclohexyl derivatives show almost no catalytic activity, whereas for the tert ‐butyl derivatives a significant difference could be observed, depending on whether the seven‐membered ring or the five‐membered ring is functionalized.