Issue 15, 2023

Fragile intermediate identification and reactivity elucidation in electrochemical oxidative α-C(sp3)–H functionalization of tertiary amines

Abstract

The direct α-C(sp3)–H functionalization of widely available tertiary amines holds promise for the rapid construction of complex amine architectures. The activation of C(sp3)–H bonds through electron transfer and proton transfer by oxidants, photoredox catalysis and electrochemical oxidation have received wide attention recently. In these reactions, the direct capture and identification of the key reactive radical intermediates are technically difficult due to their short life-time. Herein, an online electrochemical mass spectrometry (MS) methodology was utilized to probe the short-lived intermediates in the electrochemical oxidative α-C(sp3)–H functionalization of tertiary amines. The resulting electrochemical oxidation intermediates, α-amino radical cation and iminium cation were successfully detected. Further, the α-amino C(sp3) radical added to the double bond of a phenyl trans-styryl sulfone, yielding another C(sp3) radical that leads to the final vinylation. Based on the mass spectrometric elucidation of the reactivity of the α-amino radical, a scale-up electrochemical radical vinylation methodology was established, with which a large variety of allylic amines with broad functional group tolerance were synthesized.

Graphical abstract: Fragile intermediate identification and reactivity elucidation in electrochemical oxidative α-C(sp3)–H functionalization of tertiary amines

Supplementary files

Article information

Article type
Edge Article
Submitted
31 jan 2023
Accepted
17 mar 2023
First published
18 mar 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, 4152-4157

Fragile intermediate identification and reactivity elucidation in electrochemical oxidative α-C(sp3)–H functionalization of tertiary amines

K. Liang, D. Zhang, Y. Su, L. Lu, J. Hu, Y. Chen, X. Zhang, A. Lei and H. Yi, Chem. Sci., 2023, 14, 4152 DOI: 10.1039/D3SC00527E

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