Catalytic Regioselective Olefin Hydroarylation(alkenylation) by Sequential Carbonickelation-Hydride Transfer

Alkene hydrocarbofunctionalization represents one of the most important classes of chemical transformations, but related branched-selective examples with unactivated olefins are scarce. Here, we report that catalytic amounts of a dimeric Ni(I) complex and an exogenous alkoxide base promote Markovnikov-selective hydroarylation(alkenylation) of unactivated and activated olefins using organo bromides or triflates derived from widely available phenols and ketones. Products bearing aryl- and alkenyl-substituted tertiary and quaternary centers could be isolated in up to 95% yield and >99:1 regioisomeric ratios. Contrary to previous dual-catalytic methods that rely on metal-hydride atom transfer (MHAT) to the olefin prior to carbofunctionalization with a cocatalyst, our mechanistic evidence points toward a nonradical reaction pathway that begins with site-selective carbonickelation across the C=C bond followed by hydride transfer using alkoxide as the hydride source. Utility of the single-catalyst protocol is highlighted through the synthesis of medicinally relevant scaffolds.

Automated summary

This study presents a catalytic protocol using a dimeric Ni(I) complex and an exogenous alkoxide base for the selective hydroarylation of unactivated and activated olefins. The reaction leads to the formation of products containing aryl- and alkenyl-substituted tertiary and quaternary centers, with high yields and regioisomeric ratios. The mechanism involves carbonickelation followed by hydride transfer using alkoxide as the hydride source, showcasing the utility of this single-catalyst protocol for the synthesis of medicinally relevant scaffolds.