The
exploration into challenging scenarios of the application of
elementary reactions offers excellent opportunities for the development
of unique transformations under organometallic catalysis. As a ubiquitous
reaction of metal alkyl complexes, β-hydride elimination plays
a crucial role in a number of important catalytic transformations.
However, its functions in these catalytic cycles are limited to either
releasing alkene products or generating isomerized intermediates through
further migratory insertion. Herein, we report that the precise manipulation
of β-hydride elimination enables an auto-tandem copper catalysis
for the carboxylation of undirected alkenyl C–H bonds with
CO2. In this transformation, β-hydride elimination
of an alkyl copper intermediate is facilitated, while its reaction
with CO2 is suppressed. The resulting copper hydride in
turn reacts with CO2 to provide access to a multitasking
catalyst, which enables the tandem borylation/carboxylation of C–H
bonds in two mechanistically distinct catalytic cycles.