TY - JOUR
T1 - A General Iron-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids
AU - Denkler, Luca Mareen
AU - Aladahalli Shekar, Meghana
AU - Ngan, Tak Shing Jason
AU - Wylie, Luke
AU - Abdullin, Dinar
AU - Engeser, Marianne
AU - Schnakenburg, Gregor
AU - Hett, Tobias
AU - Pilz, Frank Hendrik
AU - Kirchner, Barbara
AU - Schiemann, Olav
AU - Kielb, Patrycja
AU - Bunescu, Ala
N1 - Publisher Copyright:
© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.
PY - 2024/8/5
Y1 - 2024/8/5
N2 - We report an iron-catalyzed decarboxylative C(sp3)−O bond-forming reaction under mild, base-free conditions with visible light irradiation. The transformation uses readily available and structurally diverse carboxylic acids, iron photocatalyst, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) derivatives as oxygenation reagents. The process exhibits a broad scope in acids possessing a wide range of stereoelectronic properties and functional groups. The developed reaction was applied to late-stage oxygenation of a series of bio-active molecules. The reaction leverages the ability of iron complexes to generate carbon-centered radicals directly from carboxylic acids by photoinduced carboxylate-to-iron charge transfer. Kinetic, electrochemical, EPR, UV/Vis, HRMS, and DFT studies revealed that TEMPO has a triple role in the reaction: as an oxygenation reagent, an oxidant to turn over the Fe-catalyst, and an internal base for the carboxylic acid deprotonation. The obtained TEMPO adducts represent versatile synthetic intermediates that were further engaged in C−C and C-heteroatom bond-forming reactions using commercial organo-photocatalysts and nucleophilic reagents.
AB - We report an iron-catalyzed decarboxylative C(sp3)−O bond-forming reaction under mild, base-free conditions with visible light irradiation. The transformation uses readily available and structurally diverse carboxylic acids, iron photocatalyst, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) derivatives as oxygenation reagents. The process exhibits a broad scope in acids possessing a wide range of stereoelectronic properties and functional groups. The developed reaction was applied to late-stage oxygenation of a series of bio-active molecules. The reaction leverages the ability of iron complexes to generate carbon-centered radicals directly from carboxylic acids by photoinduced carboxylate-to-iron charge transfer. Kinetic, electrochemical, EPR, UV/Vis, HRMS, and DFT studies revealed that TEMPO has a triple role in the reaction: as an oxygenation reagent, an oxidant to turn over the Fe-catalyst, and an internal base for the carboxylic acid deprotonation. The obtained TEMPO adducts represent versatile synthetic intermediates that were further engaged in C−C and C-heteroatom bond-forming reactions using commercial organo-photocatalysts and nucleophilic reagents.
KW - Carboxylic acid
KW - Iron
KW - Oxygenation
KW - Photocatalysis
KW - TEMPO
UR - http://www.scopus.com/inward/record.url?scp=85197440564&partnerID=8YFLogxK
U2 - 10.1002/anie.202403292
DO - 10.1002/anie.202403292
M3 - Article
AN - SCOPUS:85197440564
SN - 1433-7851
VL - 63
JO - Angewandte Chemie International Edition in English
JF - Angewandte Chemie International Edition in English
IS - 32
M1 - e202403292
ER -