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Updated: Jan 27, 2026

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Proton-Coupled Electron Transfer: Transition-Metal-Free Selective Reduction of Chalcones and Alkynes Using
Ramanathan Prasanna1, Somraj Guha1, Govindasamy Sekar1
1Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , Tamil Nadu , India.
Abstract:
Highly chemoselective reduction of α,β-unsaturated ketones to saturated ketones and stereoselective reduction of alkynes to ( E)-alkenes has been developed under a transition-metal-free condition using a xanthate/formic acid mixture through proton-coupled electron transfer (PCET). Mechanistic experiments and DFT calculations support the possibility of a concerted proton electron-transfer (CPET) pathway. This Birch-type reduction demonstrates that a small nucleophilic organic molecule can be used as a single electron-transfer (SET) reducing agent with a proper proton source.
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