Photoinduced N-Heterocyclic Nitrenium-Catalyzed Single Electron Reduction of Acyl Fluorides for Phenanthridine Synthesis

Abstract

Acyl fluorides are versatile reagents in organic synthesis. However, there is no precedent to employ acyl fluorides as acyl radical precursors. We herein report an N-heterocyclic nitrenium iodide salt-catalyzed photoreduction of acyl fluorides to produce acyl radicals, which could react with 2-isocyanobiaryls to afford various carbonyl phenanthridines.

Visible‐Light‐Driven Sulfonamidation of Arylazo Sulfonesthrough One‐Pot Multicomponent Reaction

“…[27,29] Typically, photochemical methods are effectively used for reactions involving radical pathways to form CÀ C coupling or carbon-heteroatom bonds. [30][31][32][33][34][35][36][37][38] However, photochemical reactions often require expensive photocatalysts such as complexes of Ir or Ru metals or dye compounds. [39][40][41][42] Therefore, it is useful to develop novel photocatalyst-free photochemical reactions.…”

“…Light energy can activate substrates and produce organic reactions under mild conditions [27,29] . Typically, photochemical methods are effectively used for reactions involving radical pathways to form C−C coupling or carbon‐heteroatom bonds [30–38] . However, photochemical reactions often require expensive photocatalysts such as complexes of Ir or Ru metals or dye compounds [39–42] .…”

Unified Approach to Diverse Heterocyclic Synthesis: Organo-Photocatalyzed Carboacylation of Alkenes and Alkynes from Feedstock Aldehydes and Alcohols

“…In recent years, visible-light-induced photocatalysis has emerged as a green and sustainable route with high synthetic potential . The generation of acyl radicals at room temperature under mild conditions has been made possible by utilizing photoredox strategies .…”

Nitrenium ions as new versatile reagents for electrophilic amination

“…This form demonstrates a nitrogen nonoctet character in these ions, which possess a relatively low LUMO and a free p-orbital on the central N-atom. These unique properties of NHNs allowed us and others to demonstrate that NHNs can act as nitrogen-based Lewis acids, [29][30][31][32][33] activators of strong bonds through frustrated Lewis pair chemistry, 30,34 catalytic Lewis acids for several reactions, [35][36][37][38] photocatalysts [39][40][41] and a platform for stable nitrogen-based radicals. 42,43 Exploring this Lewis acidity, we previously demonstrated that NHN 1 reacts with phenyllithium or n-butyllithium to furnish cyclic triazanes 2 (Scheme 2b).…”