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Ligand Control in Selective C–H Oxidative Functionalization Using Pd‐PEPPSI‐Type Complexes
Author(s) -
Bolbat Ekaterina,
Wendt Ola F.
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600322
Subject(s) - chemistry , ligand (biochemistry) , selectivity , catalysis , palladium , steric effects , combinatorial chemistry , yield (engineering) , surface modification , oxidative addition , stereochemistry , organic chemistry , receptor , materials science , metallurgy , biochemistry
To achieve high selectivity in directed C–H activation, an NHC ligand was introduced to a palladium catalyst. A range of Pd‐PEPPSI complexes were applied in the direct acetoxylation of 2‐phenylpyridine. The best catalyst was found to be the one based on a diisopropylphenyl‐substituted NHC ligand, and this was successfully used for the functionalization of sp 2 as well as more challenging sp 3 bonds for a broad variety of substrates. The explored method showed a highly improved selectivity compared to previously reported results with up to 96 % yield for the monoacetoxylated product. Kinetic studies show that sterics of the catalyst is less important in dictating conversion and selectivity; despite an induction period, it was shown that the catalyst is molecular in nature.