Olefin functionalization/isomerization enables stereoselective alkene synthesis

Despite tremendous efforts aimed at devising methods for stereoselective alkene synthesis, critical challenges are yet to be addressed. Direct access to a diverse range of 1-aryl(boryl)-1-methyl-functionalized tri- and tetrasubstituted trans alkenes, entities that are prevalent in many important molecules, through a catalytic manifold from readily available α-olefin substrates remains elusive. Here, we demonstrate that catalytic amounts of a non-precious N -heterocyclic carbene–Ni(I) complex in conjunction with a sterically bulky base promote site- and trans -selective union of monosubstituted olefins with a wide array of electrophilic reagents to deliver tri- and tetrasubstituted alkenes in up to 92% yield and >98% regio- and stereoselectivity. The protocol is amenable to the preparation of carbon- and heteroatom-substituted C=C bonds, providing distinct advantages over existing transformations. Utility is highlighted through concise stereoselective synthesis of biologically active compounds.