Nickel catalysis acylation

Copper(I) and metals of the nickel triad have been used to effect allylation, aryladon, vinylation and acylation reactions of zinc homoenolates. Transient homoenolates generated under Pd catalysis and Ag catalysis have also been used for direct arylation and acylation of silyloxycyclopropanes. 

The first compound described as an artificial enzyme in the literature was the one we reported in which we attached a metal ion binding group to a-cyclodextrin. We found that this would bind p-nitrophenyl acetate into the cavity and a bound nickel ion then catalysed the hydrolysis of the substrate. This was a direct hydrolysis, not an acylation of a cyclodextrin hydroxyl (which is not in reach with the para esters). This type of catalyst then extends metal-catalysed reactions to substrates that do not intrinsically bind to metal ions, which was formerly required for such catalysis. 

As an alternative to palladium and ruthenium catalysts as racemization agents, De Vos and coworkers reported the use of Raney nickel for the DKR of aliphatic amines in toluene and a low pressure of hydrogen (0.01-0.02 MPa) at 70 °C. Its combination with CAL-B and EtOAcMeOAc led to the desired (R)-methoxyacetamides in 64—98% conversion and 80-98% ee [245], The production of optically active amines has been also possible using ketoximes instead of racemic amines as starting materials, and using metal catalysis for the racemization step. Thus, Kim and coworkers reported the asymmetric reductive acylation a system including the use of palladium on charcoal for the reduction/racemization sequence in combination with CAL-B, 2 equivalents of EtOAc, three equivalents of diisopropylethylamine, and 1 Hjatm in toluene at... 

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