Three-component alkene 1,2-difunctionalizations have
emerged as
a powerful strategy for rapid buildup of diverse and complex alkylpyridines,
but the distal functionalized alkyl radicals for the alkene 1,2-alkylpyridylations
were still rare. Herein, we report an example of regioselective three-component
1,2-cyanoalkylpyridylation of feedstock styrenes with accessible nonredox-active
cyclic oximes through visible-light photoredox catalysis, providing
a series of structurally diverse β-cyanoalkylated alkylpyridines.
This protocol proceeds through a radical relay pathway including the
generation of iminyl radicals enabled by phosphoranyl radical-mediated
β-scission, radical transposition through C–C bond cleavage,
highly selective radical addition, and precise radical–radical
cross-coupling sequence, thus facilitating the regioselective formation
of two distinct C–C single bonds in a single-pot operation.
This synthetic strategy features mild conditions, broad compatibility
of functional groups and substrate scope, diverse product derivatization,
and late-stage modification.