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Synfacts 2021; 17(07): 0765
DOI: 10.1055/s-0040-1706241
Metals in Synthesis

Nickel-Mediated C(sp3)–H Methylation via Photochemical Activation of Peroxides

Contributor(s):
Mark Lautens
,
Jeanne Masson-Makdissi
Vasilopoulos A, Krska SW, Stahl SS. * University of Wisconsin, Madison, USA
C(sp3)–H Methylation Enabled by Peroxide Photosensitization and Ni-Mediated Radical Coupling.

Science 2021;
372: 398-403
DOI: 10.1126/science.abh2623.
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Key words

nickel catalysis - C(sp3)–H activation - methylation

Significance

A novel method for late-stage C(sp3)–H methylation is reported. An iridium photocatalyst is used for the activation of peroxide, the latter serving as both an oxidant for C–H cleavage and a source of methyl radical. The nickel catalyst is essential to enable formal recombination of two different radical species and promote C–C bond formation; in its absence, the methyl radical undergoes unproductive H atom transfers (HAT).


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Comment

The authors thoroughly studied the effects of solvent, temperature, concentration, and nature of peroxide on the relative rates of HAT vs. methyl radical formation. As the rates of HAT differ from substrate to substrate, the results of these studies were used as a guide during the investigation of the reaction scope; different set of conditions were developed, enabling the methylation of various substrate classes.


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Publication History

Article published online:
17 June 2021

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