Nickel-Catalyzed Electrochemical Couplings of Vinyl Halides:  Synthetic and Stereochemical Aspects

Abstract

Homo- and cross-coupling involving alkenyl halides have been performed efficiently using an electroassisted nickel-complex catalysis. Valuable product such as conjugated dienes, beta,gamma- or gamma,delta-unsaturated esters, ketones, or nitriles, as well as alkenylated aryl compounds are thus prepared with high yields and high stereoselectivity. Partial isomerization is only observed in a few cases, when the alkenyl halide is involved in a late step of the catalytic cycle. This is the case in the preparation of (Z,Z)-1,3-diene.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

“…758 Mechanistically, the oxidative insertion of an electrogenerated Ni(0) catalyst into C–X bonds gives rise to a Ni(II) complex which could undergo cathodic reduction to yield an aryl-Ni(I) intermediate. This intermediate can participate in a second iteration of oxidative addition whereupon a reductive elimination affords the coupling product (see Figure 44E for a simplified mechanistic picture).…”

Nickel-Catalyzed Asymmetric Reductive Cross-Coupling between Heteroaryl Iodides and α-Chloronitriles

“…Furthermore, α-chloronitriles have not been developed as C(sp 3 ) electrophiles for Ni-catalyzed reductive cross-coupling reactions (even in the racemic sense). 11 Thus, the successful development of this transformation would expand the scope of reductive cross-coupling reactions to new and synthetically versatile classes of electrophiles.…”

Nickel Bromide Bipyridine

“…20 To our knowledge, sp 3 -sp 3 heterocouplings catalyzed by NiBr 2 bipy have never been described, while sp 2 -sp 3 ones are known (see below). An appealing application of this chemistry is the synthesis of fully sp 2 polymeric materials, starting from dihalo (mainly dibromo) aromatic or heteroaromatic monomers.…”