Nickel-catalyzed hydroamination

Fig. 12) [91 ]. This phosphine-carbene ligand has been used in the nickel catalyzed hydroamination of acrylonitrile derivatives [92]. 

A nickel-catalyzed hydroamination of acrylonitrile using cationic pincer complexes has been described (Scheme 3-109). Mechanistic studies suggested that a simple Lewis acidic role of nickel may be responsible for the catalysis in this group... 

SCHEME 5.40 Asymmetric intra-molecular nickel-catalyzed hydroamination of alkenes. 

Asymmetric Intra-Molecular Nickel-Catalyzed Hydroamination of Alkenes... 

SCHEME 3.126 Nickel catalyzed hydroamination of activated internal alkynes [138],... 

Nickel-catalyzed hydroamination of conjugated dienes at room temperature has been shown to be an efficient synthesis of allylamines in excellent yields [262],... 

Following early studies of the nickel-catalyzed coupling of dienes with amines to generate mixtures of 1 1 and 2 1 adducts a high-throughput colorimetric assay discovered that the catalyst derived from Ni(cod)2 and dppf efficiently catalyzes the 1 1 hydroamination of 1,3-dienes with primary or secondary amines to produce allylic amine products (Scheme 3-107). A catalytic quantity of trifluoroacetic acid was a key component in the optimized procedure. 

In addition to simple hydroamination processes, nickel-catalyzed alkene diaminations have been developed under oxidative conditions (Scheme 3-110). Treatment of sulfamide substrates with PhI(OAc)2 in the presence of Ni(acac)2 as catalyst directly provides diamination products. This key report suggests that further related developments in oxidative nickel catalysis are likely. 

More recently, the hydroamination of butadiene, isoprene, and cyclohexadiene to form 1 1 adducts with high selectivity catalyzed by nickel and palladium complexes has... 

Common nickel compounds have been used to catalyze the hydroamination of internal activated alkenes (Scheme 3.126) [138]. The reactions were carried out under a high pressure of argon and afforded moderate yields of the enamines. While activated internal alkenes were successfully functionalized using this approach, unactivated substrates such as diphenylacetylene were unreactive and afforded low conversions (-30%). 

Reduced nickel salts in the presence of a large amount of phosphine catalyze the hydroamination of 1,3-butadiene with EtjNH (Eq. 4.44) [175, 176]. 

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