The research group of Lan-Gui Xie from Nanjing Normal University has conducted a series of studies, using
N-aryl glycinate substrates which can produce captodatively-stabilized [
1] carbon-centered radicals under photoredox catalytic conditions. The coupling between glycinate derived radical and transient carbon radical generated from the addition of functional fragment to alkene is enabled by the captodative stability of the former [
2]. Building on these findings, they have previously developed a visible-light-induced carbosulfenylation of styrenes with
N-aryl glycinates/peptides and disulfides [
3]. Very recently, Xie’s group further developed the photoredox-catalyzed three-component arylative/azido alkylation of amino acid and peptide derivatives using aryl thianthrenium salts/TMSN
3 and alkenes (
Scheme 1) [
4,
5]. In these protocols, blue light irradiation initiates the generation of the excited state of the photocatalyst, which engages in electron transfer process-abstracting an electron from
N-aryl glycinate to form a captodatively-stabilized carbon-centered radical under base conditions. An aryl radical is able to be generated through the single electron transfer between the aryl thianthrenium salt and the photocatalyst. While the other radical precursor TMSN
3 has the potential to be oxidized by SF
6 radical anion that is generated from the contact of electron scavenger SF
6 and the photocatalyst. These two types of radicals can be trapped by styrene/alkene to generate benzyl radical, which undergoes radical-radical coupling with the stabilized carbon radical to give products.