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Synfacts 2025; 21(07): 702
DOI: 10.1055/a-2601-4161
Metals in Synthesis

Accessing Cyclopropenes and Oxazoles from α-Diazoesters under Cobalt Metalloradical Catalysis

Contributor(s):
Mark Lautens 
,
Justin Ching
Tan L, Wu K, Li G *. Utah State University, Logan, USA
Cobaloxime-Based Metalloradical Catalysis: A Versatile Strategy for the Synthesis of Cyclopropenes and Oxazoles.

Angew. Chem. Int. Ed. 2025;
DOI: 10.1002/anie.202500667
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Keywords

cobalt catalysis - cyclopropenes - oxazoles

Significance

Li and co-workers report the use of a cobaloxime catalyst in two divergent metalloradical cyclization strategies. The α-Co-alkyl radical intermediate can participate in either a radical [2 + 1] cyclization to form a cyclopropene from an alkyne, or a radical [3 + 2] cyclization to form an oxazole from a nitrile.


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Comment

The authors performed TEMPO trapping experiments to verify the presence of radicals. Addition of TEMPO to either cyclization conditions resulted in diminished yields of both cyclopropene and oxazole products, and the formation of a TEMPO adduct at the α-position of the ester.


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Publication History

Article published online:
23 June 2025

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