1816-01-9Relevant articles and documents
Selective C-4 alkylation of pyridine by nickel/Lewis acid catalysis
Nakao, Yoshiaki,Yamada, Yuuya,Kashihara, Natsuko,Hiyama, Tamejiro
supporting information; experimental part, p. 13666 - 13668 (2010/11/24)
Direct C-4-selective addition of pyridine across alkenes and alkynes is achieved for the first time by nickel/Lewis acid cooperative catalysis with an N-heterocyclic carbene ligand. A variety of substituents on both alkenes and pyridine are tolerated to give linear 4-alkylpyridines in modest to good yields. The addition across styrene, on the other hand, gives branched 4-alkylpyridines. A single example of C-4-selective alkenylation is also described.
Selective Functionalisation. Part 11. Selective Hydrogenation by a Novel Palladium Salicylidene-ethylenediamine Complex and the Properties of Derivatives of some Square Planar Homogenous Hydrogenation Catalysts.
Kerr, James M.,Suckling, Colin J.,Bamfield, Peter
, p. 887 - 895 (2007/10/02)
Analogues of two reported homogenous hydrogenation catalysts based upon square planar palladium complexes have been prepared with a view to modifying the structures to permit the control of selectivity by micellar interactions.Derivatives of bisacetylacetonatopalladium(II) in which the diketone was alkylated at C-3 or C-5 were prepared but no useful catalytic activity was observed for the reduction of nitrobenzene to aniline in the presence of pyridine.Complexes were also prepared from bisacetylacetonatopalladium(II) with 4-substituted pyridines as ligands; 4-tridecylpyridine afforded an unstable complex but 4-decylaminopyridine afforded a stable complex with low catalytic activity.A series of salicylidene imine palladium(II) complexes was prepared.Contrary to previous reports, the well-known salicylidene-ethylenediaminepalladium(II) complex was not a catalyst for homogenous hydrogenation but a new oligomeric green heterogenous complex with selective hydrogenation properties was discovered.This green complex was selective for the hydrogenation of alkynes, especially terminal alkynes, and reduced few other functional groups (ArNO2, ArCHO).Many variations on this structure were investigated in an attempt to discover a soluble or crystalline analogue of the green complex but no complexes with improved properties were isolated.
