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We report herein an ortho‐C–H alkenylation reaction of aryl imines with alkenyl phosphates promoted by a cobalt–N‐heterocyclic carbene (NHC) catalytic system. While commercially available bulky NHC ligands exhibited only modest catalytic activity, elaboration of the nitrogen substituents and backbone of the NHC enabled the desired transformation to proceed in high yield at a mild temperature. The new Co–NHC system proved applicable to a variety of aryl imines and alkenyl phosphates to afford ortho‐alkenylated aryl imines, which serve as precursors to benzofulvene derivatives. MOE (Min. of Education, S’pore) Accepted version

A cobalt–chiral phosphoramidite catalyst promotes enantioselective imine-directed C2-alkylation of Boc-protected indoles with styrenes. The reaction affords 1,1-diarylethane products in moderate to good yields with good enantioselectivities under mild conditions. A deuterium-labeling experiment suggests that the enantioselectivity is controlled by both the styrene insertion and the C–C reductive elimination steps. Accepted version

A cobalt–chiral phosphoramidite catalyst promotes enantioselective imine-directed C2-alkylation of Boc-protected indoles with styrenes. The reaction affords 1,1-diarylethane products in moderate to good yields with good enantioselectivities under mild conditions. A deuterium-labeling experiment suggests that the enantioselectivity is controlled by both the styrene insertion and the C–C reductive elimination steps.

An improved cobalt-based catalytic system has been developed for the branched-selective addition of aromatic ketimines to styrenes. With an appropriate combination of triarylphosphine and the Grignard reagent, the reaction takes place smoothly at room temperature to afford 1,1-diarylethane derivatives with high regioselectivity.

An improved cobalt-based catalytic system has been developed for the branched-selective addition of aromatic ketimines to styrenes. With an appropriate combination of triarylphosphine and the Grign...

The Co(II)/imidazolium catalyst in combination with neopentylmagnesium bromide allows arylation at room temperature.

A quaternary catalytic cobalt system promotes the hydroarylation of internal alkynes with aromatic imines through chelation-assisted C—H bond cleavage.

An ortho-arylation reaction of aromatic imines with aryl chlorides has been achieved using a cobalt–N-heterocyclic carbene catalyst in combination with a neopentyl Grignard reagent. The reaction takes place at room temperature to afford biaryl products in moderate to good yields.

Chelation-controlled addition of arylpyridines or aromatic imines towards internal alkynes proceeds readily in the presence of a CoBr2—monophosphine catalyst to give tri-substituted olefins with high regio- and stereoselectivities in most cases.

Ternary catalytic systems consisting of cobalt salts, phosphine ligands, and Grignard reagents promote addition of arylpyridines and imines to unactivated internal alkynes with high regio- and stereoselectivities. Deuterium-labeling experiments suggest that the reaction involves chelation-assisted oxidative addition of the aryl C−H bond to the cobalt center and insertion of the C−C triple bond into the Co−H bond, followed by reductive elimination of the resulting diorganocobalt species.