Dirhodium-Catalyzed Transannulation of N‑Sulfonyl-1,2,3-triazoles to 2,3-Dehydropiperazines

The dirhodium­(II)-catalyzed synthesis of a range of C2-substituted 2,3-dehydropiperazines using 1-mesyl-1,2,3-triazoles and β-haloalkylcarbamates is reported. The reaction is proposed to proceed through an α-imino rhodium carbene 1,3-insertion into N–H followed by a base-mediated cyclization. C-Sub...

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Bibliographic Details
Published in:Journal of organic chemistry 2023-08, Vol.88 (16), p.11968-11979
Main Authors: Nutt, Michael J., Annear, Jack W., Jones, Kieran D., Flematti, Gavin R., Moggach, Stephen A., Stewart, Scott G.
Format: Article
Language:English
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Summary:The dirhodium­(II)-catalyzed synthesis of a range of C2-substituted 2,3-dehydropiperazines using 1-mesyl-1,2,3-triazoles and β-haloalkylcarbamates is reported. The reaction is proposed to proceed through an α-imino rhodium carbene 1,3-insertion into N–H followed by a base-mediated cyclization. C-Substituted dehydropiperazines can also be conducted directly from terminal alkynes in a three-step, one-pot operation, forming the triazole in situ. This methodology has also been expanded to afford several 2,5-disubstituted 2,3-dehydropiperazines as well as a larger 4,5,6,7-tetrahydro-1H-1,4-diazepine derivative.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.3c01259