Issue 26, 2023

Cobalt-catalyzed enantioselective C–H/N–H annulation of aryl sulfonamides with allenes or alkynes: facile access to C–N axially chiral sultams

Abstract

Herein we report a cobalt-catalyzed enantioselective C–H/N–H annulation of aryl sulfonamides with allenes and alkynes, using either chemical or electrochemical oxidation. By using O2 as the oxidant, the annulation with allenes proceeds efficiently with a low catalyst/ligand loading of 5 mol% and tolerates a wide range of allenes, including 2,3-butadienoate, allenylphosphonate, and phenylallene, resulting in C–N axially chiral sultams with high enantio-, regio-, and position selectivities. The annulation with alkynes also exhibits excellent enantiocontrol (up to >99% ee) with a variety of functional aryl sulfonamides, and internal and terminal alkynes. Furthermore, electrochemical oxidative C–H/N–H annulation with alkynes is achieved in a simple undivided cell, demonstrating the versatility and robustness of the cobalt/Salox system. The gram-scale synthesis and asymmetric catalysis further highlight the practical utility of this method.

Graphical abstract: Cobalt-catalyzed enantioselective C–H/N–H annulation of aryl sulfonamides with allenes or alkynes: facile access to C–N axially chiral sultams

Supplementary files

Article information

Article type
Edge Article
Submitted
06 apr 2023
Accepted
08 iyn 2023
First published
08 iyn 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2023,14, 7291-7303

Cobalt-catalyzed enantioselective C–H/N–H annulation of aryl sulfonamides with allenes or alkynes: facile access to C–N axially chiral sultams

X. Si, X. Zhao, J. Wang, X. Wang, Y. Zhang, D. Yang, M. Song and J. Niu, Chem. Sci., 2023, 14, 7291 DOI: 10.1039/D3SC01787G

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