Hydroalkylation of Unactivated Olefins via Visible-Light-Driven Dual Hydrogen Atom Transfer Catalysis

Radical hydroalkylation of olefins enabled by hydrogen atom transfer (HAT) catalysis represents a straightforward means to access C(sp(3))-rich molecules from abundant feedstock chemicals without the need for prefunctionalization. While Giesetype hydroalkylation of activated olefins initiated by HAT of hydridic carbon-hydrogen bonds is well-precedented, hydroalkylation of unactivated olefins in a similar fashion remains elusive, primarily owing to a lack of general methods to overcome the inherent polarity-mismatch in this scenario. Here, we report the use of visible-light-driven dual HAT catalysis to achieve this goal, where catalytic amounts of an amine-borane and an in situ generated thiol were utilized as the hydrogen atom abstractor and donor, respectively. The reaction is completely atom-economical and exhibits a broad scope. Experimental and computational studies support the proposed mechanism and suggest that hydrogen-bonding between the amine-borane and substrates is beneficial to improving the reaction efficiency.

Automated summary

This study demonstrates the radical hydroalkylation of unactivated olefins using visible-light-driven dual HAT catalysis, with catalytic amounts of amine-borane and in situ generated thiol as the hydrogen atom abstractor and donor. Experimental and computational studies support the proposed mechanism, suggesting that hydrogen bonding between the amine-borane and substrates improves reaction efficiency.