posted on 2023-12-15, 16:10authored bySourav Pradhan, Jeonguk Kweon, Manoj Kumar Sahoo, Hoimin Jung, Joon Heo, Yeong Bum Kim, Dongwook Kim, Jung-Woo Park, Sukbok Chang
Harnessing
the key intermediates in metal-catalyzed reactions is
one of the most essential strategies in the development of selective
organic transformations. The nitrogen group transfer reactivity of
metal-nitrenoids to ubiquitous C–H bonds allows for diverse
C–N bond formation to furnish synthetically valuable aminated
products. In this study, we present an unprecedented reactivity of
iridium and ruthenium nitrenoids to generate remote carbocation intermediates,
which subsequently undergo nucleophile incorporation, thus developing
a formal γ-C–H functionalization of carboxylic acids.
Mechanistic investigations elucidated a unique singlet metal-nitrenoid
reactivity to initiate an abstraction of γ-hydride to form the
carbocation intermediate that eventually reacts with a broad range
of carbon, nitrogen, and oxygen nucleophiles, as well as biorelevant
molecules. Alternatively, the same intermediate can lead to deprotonation
to afford β,γ-unsaturated amides in a less nucleophilic
solvent.