A biomimetic SH2 cross-coupling mechanism for quaternary sp3-carbon formation

Wei Liu, Marissa N. Lavagnino, Colin A. Gould, Jesús Alcázar, David W.C. MacMillan

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Bimolecular homolytic substitution (SH2) is an open-shell mechanism that is implicated across a host of biochemical alkylation pathways. Surprisingly, however, this radical substitution manifold has not been generally deployed as a design element in synthetic C–C bond formation. We found that the SH2 mechanism can be leveraged to enable a biomimetic sp3-sp3 cross-coupling platform that furnishes quaternary sp3-carbon centers, a long-standing challenge in organic molecule construction. This heteroselective radical-radical coupling uses the capacity of iron porphyrin to readily distinguish between the SH2 bond-forming roles of open-shell primary and tertiary carbons, combined with photocatalysis to generate both radical classes simultaneously from widely abundant functional groups. Mechanistic studies confirm the intermediacy of a primary alkyl–Fe(III) species prior to coupling and provide evidence for the SH2 displacement pathway in the critical quaternary sp3-carbon bond formation step.

Original languageEnglish (US)
Pages (from-to)1258-1263
Number of pages6
Issue number6572
StatePublished - Dec 3 2021

All Science Journal Classification (ASJC) codes

  • General


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