No abstract

This review discusses the applications of N-heterocyclic carbene ligands and their influence on the reactivity and selectivity of Ni-catalysed alkene functionalisations.

Catalytic strategies that provide stereoselective access to highly substituted alkenes from abundant monosubstituted substrates are exceedingly sought-after but rare. Here, we show that a N-heterocyclic carbene-Ni I catalytic species mediates efficient union of electronically polarized terminal olefins with benzyl chlorides, in the presence of trimethylsilyl triflate and trimethylamine additives, to generate trisubstituted boron-and arene-containing trans alkenes in excellent regio-and stereoselectivities. Control experiments provide evidence for a mechanism involving branchedselective Heck-type benzylation that overrides substrate control, followed by trans-selective 1,3-hydrogen shift. The method represents a significant addition to the toolbox of reactions for the concise synthesis of unsaturated biologically active compounds.

Catalytic strategies that provide stereoselective access to highly substituted alkenes from abundant monosubstituted substrates are exceedingly sought‐after but rare. Here, we show that a N‐heterocyclic carbene‐NiI catalytic species mediates efficient union of electronically polarized terminal olefins with benzyl chlorides, in the presence of trimethylsilyl triflate and trimethylamine additives, to generate trisubstituted boron‐ and arene‐containing trans alkenes in excellent regio‐ and stereoselectivities. Control experiments provide evidence for a mechanism involving branched‐selective Heck‐type benzylation that overrides substrate control, followed by trans‐selective 1,3‐hydrogen shift. The method represents a significant addition to the toolbox of reactions for the concise synthesis of unsaturated biologically active compounds.