A palladium‐catalyzed protocol for the halogenation of [2.2]paracyclophanes by C–H activation is described, and ortho selectivity is achieved with an O‐methyloxime directing group. Bromination and iodination of the sterically demanding [2.2]paracyclophane proceed in good yields with inexpensive and readily available N‐halosuccinimides. Deprotection of the O‐methyloximes yields ortho‐halogenated aldehydes as attractive intermediates for the modular synthesis of 4,5‐disubstituted [2.2]paracyclophanes. The synthetic value of this protocol was demonstrated by exemplary conversions of the carbaldehyde and halogen site. Additionally, early stage resolution and subsequent bromination/deprotection provides the brominated aldehyde in enantiopure form.
A series of novel Pd@DE-HKUST-1(Cu/Pd) catalysts with different pydc feeding ratios were successfully synthesized. The size regime and the spatial distribution of the Pd NPs can be controlled by the amount of framework incorporated pydc.
New single‐site catalysts based on mixed‐linker metal‐organic frameworks with DUT‐5 structure, which contain immobilized Co2+, Mn2+ and Mn3+ complexes, have successfully been synthesized via post‐synthetic modification. 2,2’‐Bipyridine‐5,5’‐dicarboxylate linkers were directly metalated, while 2‐amino‐4,4’‐biphenyldicarboxylate linkers were post‐synthetically modified by their conversion to Schiff‐base ligands and a subsequent immobilization of the metal complexes. The resulting materials were used as catalysts in the selective epoxidation of trans‐stilbene and the activities and selectivities of the different catalysts were compared. The influence of various reaction parameters on conversion, yield and selectivity were investigated. Very low catalyst amounts of 0.02 mol % were sufficient to obtain a high conversion of trans‐stilbene using molecular oxygen from air as the oxidant. For cobalt‐containing MOF catalysts, conversions up to 90 % were observed and, thus, they were more active than their manganese‐containing counterparts. Recycling experiments and hot filtration tests proved that the reactions were mainly catalyzed via heterogeneous pathways.
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