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Melder JJ, Heldner ML, Kugler R, Ziegenhagen LA, Rominger F, Rudolph M, Hashmi ASK. Easy Access to Functionalized Indolines and Tetrahydroquinolines via a Photochemical Cascade Cyclization Reaction. J Am Chem Soc 2024; 146:14521-14527. [PMID: 38743878 DOI: 10.1021/jacs.4c00962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Herein, the development of a light-mediated synthesis of functionalized indolines and tetrahydroquinolines is reported. These structural motifs are considered as highly valuable targets, attributed to their widespread occurrence in pharmaceuticals and natural products. The gold-mediated approach offers a direct route to functionalized indolines in yields of up to 81% under mild photochemical conditions. Thereby, easily accessible Boc-protected N-aryl-allylamine and homoallylamine derivatives were reacted with sp3-hybridized haloalkanes in an intermolecular cascade cyclization reaction. A broad scope of substrates, including a variety of different substituents on the aromatic backbone as well as various haloalkanes, could be utilized. Indoline derivatives, which are functionalized in position 2, are also accessible by applying ortho-allylic anilines. Moreover, the synthetic appeal was demonstrated for a total synthesis of the anti-inflammatory agent AN669 in three reaction steps in an overall yield of 64%.
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Affiliation(s)
- Julian J Melder
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Maxi L Heldner
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Robin Kugler
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Levi A Ziegenhagen
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Matthias Rudolph
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - A Stephen K Hashmi
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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