# Merging Double Hydrogen Atom Transfer and Stepwise Proton-Coupled Electron Transfer for γ‑C–H Hydrazination of Alcohols

## TL;DR

A new cobalt-catalyzed method enables efficient and sustainable conversion of alcohols into γ-hydrazino and γ-amino alcohols using a unique combination of hydrogen atom and proton-coupled electron transfers.

## Contribution

The paper introduces a novel catalytic cycle combining double hydrogen atom transfer and proton-coupled electron transfer for remote C–H functionalization.

## Key findings

- Cobalt(II) salen catalyzes γ-C–H hydrazination via a double HAT and PCET mechanism.
- Mechanistic studies confirm cobalt oxidation state changes and transient radical intermediates.
- DFT analysis supports the proposed pathway and site selectivity for functionalization.

## Abstract

A cobalt­(salen)-catalyzed
γ-C–H hydrazination of alcohols
is unveiled, merging a double hydrogen atom transfer (HAT) and a proton-coupled
electron transfer (PCET) within a single catalytic cycle. The transformation
harnesses metal–hydrogen atom transfer-induced radical translocation
and electrophilic azodicarboxylate coupling to achieve remote C–H
functionalization under mild and sustainable conditions. Mechanistic
investigations (EPR, UV–vis, and spin-trapping) reveal cobalt
oxidation state modulation and transient radical intermediates, while
DFT analysis elucidates the double HAT/PCET pathway and site selectivity.
This strategy offers an efficient and sustainable route from simple
alcohols to γ-hydrazino and γ-amino alcohols.