Transition-metal-catalyzed
cross-coupling reactions are a powerful
tool to construct carbon–carbon bonds in modern synthetic chemistry.
Chromium catalysis is much less developed compared with the widely
used palladium and nickel catalysis. Herein, we reported an efficient
and flexible chromium-catalyzed radical diacylation of alkenes with
the help of visible-light photoredox catalysis, giving access to valuable
1,4-, 1,6-, and 1,7-diones under mild conditions. The synthetic utility
of this methodology was proven by converting diones to diverse heterocycles.
Furthermore, the same dual catalysis system can be successfully applied
to dienes and vinyl cyclopropanes. A possible mechanism of alkene
diacylation via dual photoredox/chromium catalysis was proposed according
to control experiments and DFT calculations.