Visible Light‐Induced Intramolecular C─O Bond Formation via 1,5‐Hydrogen Atom Transfer Strategy

Abstract

An efficient strategy for the visible‐light‐promoted intramolecular C─O bond formation has been accomplished, which allows the synthesis of cyclic ether derivatives in the absence of a photocatalyst. This reaction is likely to occur through the generation of alkoxy radical from in situ generated O─I bond, followed by 1,5‐hydrogen atom transfer (1,5‐HAT) and subsequent intramolecular cyclization to form a C─O bond. This synthetic approach offers an efficient tool by providing access to valuable cyclic ether scaffolds under mild reaction conditions.

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

“…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] .…”

HFIP-Empowered One-Pot Synthesis of C4-Aryl-Substituted Tetrahydroquinolines with Propargylic Chlorides and Anilines

“…HFIP (1,1,1,3,3,3-hexafluoroisopropanol) has been recognized as a “magical solvent” in organic synthesis for its remarkable ability associated with hydrogen bonding . Since its first synthesis by Knunyants, HFIP has been frequently chosen as an advantageous solvent or additive . With its strong hydrogen bonding ability, HFIP promotes functionalization of C–X, C–O, CO, CN, CC, and even C–H bonds with a metal catalyst, to form new C–C or C–N bonds effectively (Scheme ).…”

Photocarboxylation of remote C–H bonds through nitrogen-centred radical 1,5-hydrogen atom transfer

“…Prompted by the interest in the nitrogen-centered-radical based 1,5-HAT strategy, researchers recently have made remarkable contributions to remote C-H bond functionalization via nitrogen-centered-radical (NCR)-triggered radical translocation processes. These innovative approaches have enabled the formation of a diverse range of bonds, including the building of C-C, 13,20 C-O, 21,22 C-N, [23][24][25][26] C-S, 27 and C-X (X = halogen) bonds. 14,19,28 Owing to its abundance, minimal toxicity, and renewability, carbon dioxide (CO 2 ), the well-known greenhouse gas, emerges as an ideal one-carbon building block for the formation of C-C bonds in organic synthesis.…”

“…4,17–19 Prompted by the interest in the nitrogen-centered-radical based 1,5-HAT strategy, researchers recently have made remarkable contributions to remote C–H bond functionalization via nitrogen-centered-radical (NCR)-triggered radical translocation processes. These innovative approaches have enabled the formation of a diverse range of bonds, including the building of C–C, 13,20 C–O, 21,22 C–N, 23–26 C–S, 27 and C–X (X = halogen) bonds. 14,19,28…”