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Radical/Polar Annulation Reactions (RPARs) Enable the Modular Construction of Cyclopropanes

John A. Milligan, James P. Phelan, Viktor C. Polites, Christopher B. Kelly*, Gary A. Molander*

*Virginia Commonwealth University, Richmond, Virginia 23284-9069; University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States, Email:,

J. A. Milligan, J. P. Phelan, V. C. Polites, C. B. Kelly, G. A. Molander, Org. Lett., 2018, 20, 6840-6844.

DOI: 10.1021/acs.orglett.8b02968

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An annulation process for the construction of 1,1-disubstituted cyclopropanes via a radical/polar crossover process proceeds by the addition of a photocatalytically generated radical to a homoallylic tosylate followed by a reduction of the intermediate radical adduct to an anion that undergoes an intramolecular substitution. The process displays excellent functional group tolerance and occurs under mild conditions with visible light irradiation.

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Redox-Neutral Photocatalytic Cyclopropanation via Radical/Polar Crossover

J. P. Phelan, S. B. Lang, J. S. Compton, C. B. Kelly, R. Dykstra, O. Gutierrez, G. A. Molander, J. Am. Chem. Soc., 2018, 140, 8037-8047.

Key Words

Cyclopropanes, Photochemistry

ID: J54-Y2018