Aryl sulfonium salt electron donor-acceptor complexes for halogen atom transfer: Isocyanides as tunable coupling partners

The photoactivation of sulfonium salt EDA (electron donor-acceptor)
complexes provides a mild platform for aryl-radical-mediated halogen
atom transfer activation of a wide range of functionalized alkyl iodides,
including tertiary alkyl iodides. Using an aryl sulfonium salt with carbon-
ate as an inexpensive donor for EDA complex formation, the general re-
action platform has been applied in a divergent, metal-free photochem-
ical approach to nitriles and amides. This divergency was made possible
by tuning the isocyanide radical traps. For example, the identification of
a readily accessible, bench-stable, and crystalline amide containing iso-
cyanide grants access to nitrile products with complete selectivity.