Synthesis 2023; 55(13): 1984-1995 DOI: 10.1055/a-2029-0345
Intramolecular Cyclization of N -Propargylic Amides without Transition-Metal Catalysis for Synthesis of Fluoroalkylated Oxazoles: Using Carboxylic Acid Anhydrides as the Fluoroalkyl Source
,
Ryohei Motegi
,
Hideki Amii∗
We would like to acknowledge the financial support of the Association for the Advancement of Science & Technology, Gunma University, JST CREST Grant Number JP MJCR21L1, and the Japan Society for the Promotion of Science (JSPS KAKENHI Grant Number 21H01927 Grant-in-Aid for Scientific Research B).
Abstract
Synthesis of 2-fluoroalkylated oxazoles was developed by transition-metal-free intramolecular cyclization of N -propargylic amides, which are prepared from propargylic amines by employing a small excess of commercially available fluorocarboxylic acid anhydrides as fluoroalkyl sources, under basic conditions. Oxazoles bearing a trifluoromethyl, pentafluoroethyl, or heptafluoropropyl group at the C2 position and functional groups on the C4 and/or C5 positions are obtained in moderate to high yields by controlling the reaction conditions.
Key words
fluoroalkyl substituents -
carboxylic acid anhydrides -
N -propargylic amides -
oxazoles -
cyclization
Supporting Information
Supporting information for this article is available online at https://doi.org/10.1055/a-2029-0345.
Supporting Information
Publication History
Received: 19 December 2022
Accepted after revision: 06 February 2023
Accepted Manuscript online: 06 February 2023
Article published online: 13 March 2023
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