Functionalization of Olefinic C-H Bonds by an Aryl-to-Vinyl 1,4-Nickel Migration/Reductive Coupling Sequence.

An attractive approach to selective functionalization of remote C-H bonds is a metal/hydride shift/cross-coupling reaction sequence. Complimentary to the heavily exploited 1,2-nickel/hydride shift along an sp chain, a chain-walking process, the 1,4-nickel/hydride shift along an sp chain is more complex. Here we report an unprecedented aryl-to-vinyl 1,4-nickel/hydride shift reaction, in which the migratory alkenylnickel species generated in situ is selectively trapped by one of various coupling partners, such as isocyanates, alkyl bromides, aryl chlorides or alkynyl bromides, allowing regio- and stereoselective access to trisubstituted alkenes.

Nickel-catalysed migratory hydroalkynylation and enantioselective hydroalkynylation of olefins with bromoalkynes.

α-Chiral alkyne is a key structural element of many bioactive compounds, chemical probes, and functional materials, and is a valuable synthon in organic synthesis. Here we report a NiH-catalysed reductive migratory hydroalkynylation of olefins with bromoalkynes that delivers the corresponding benzylic alkynylation products in high yields with excellent regioselectivities. Catalytic enantioselective hydroalkynylation of styrenes has also been realized using a simple chiral PyrOx ligand.