Pd-Catalyzed 1,3-Alkenylarylation of Skipped Diene via Metal Migration.

We disclose a palladium-catalyzed difunctionalization of skipped diene with alkenyl triflates and arylboronic acids to produce 1,3-alkenylarylated products. The reaction proceeded efficiently with Pd(acac) as a catalyst and CsF as a base for a wide range of electron-deficient and electron-rich arylboronic acids as well as oxygen-heterocyclic, sterically hindered, and complex natural product-derived alkenyl triflates bearing various functional groups. The reaction produced 3-aryl-5-alkenylcyclohexene derivatives with 1,3--disubstituted stereochemistry.

Ni-Catalyzed Regio- and Stereoselective Alkylarylation of Unactivated Alkenes in γ,δ-Alkenylketimines.

We disclose a Ni-catalyzed vicinal alkylarylation of unactivated alkenes in γ,δ-alkenylketimines with aryl halides and alkylzinc reagents. The reaction produces γ-C(sp)-branched δ-arylketones with the construction of two new C(sp)-C(sp) and C(sp)-C(sp) bonds. Electron-deficient alkenes play crucial dual roles as ligands to stabilize reaction intermediates and to increase catalytic rates for the formation of C(sp)-C(sp) bonds.

Ni(I)-Catalyzed -Vinylarylation of -Alkenyl -Cyanocarboxylic Esters via Contraction of Transient Nickellacycles.

We disclose a transmetalation-initiated Ni(I)-catalyzed regioselective -vinylarylation of -alkenyl -cyanocarboxylic esters with vinyl triflates and arylzinc reagents. This reaction proceeds via contraction of six-membered nickellacycles to five-membered nickellacycles to form carbon-carbon bonds at the nonclassical homovicinal sites, and it provides expeditious access to a wide range of complex aliphatic -cyanoesters, -cyanocarboxylic acids, dicarboxylic acids, dicarboxylic acid monoamides, monocarboxylic acids, nitriles, and spirolactones. Control, deuterium labeling, and crossover experiments indicate that (i) the nickellacycle contraction occurs by -H elimination, followed by hydronickellation on transiently formed alkenes, and (ii) the Ni species are stabilized as Ni-enolates.