Aziridines are readily available C(sp3) precursors that afford valuable β-functionalized amines upon ring opening. In this article, we report a Ni/photoredox methodology for C(sp3)–C(sp3) cross-coupling between aziridines and methyl/1°/2° aliphatic alcohols activated as benzaldehyde dialkyl acetals. Orthogonal activation modes of each alkyl coupling partner facilitate cross-selectivity in the C(sp3)–C(sp3) bond-forming reaction: the benzaldehyde dialkyl acetal is activated via hydrogen atom abstraction and β-scission via a bromine radical (generated in situ from single-electron oxidation of bromide), whereas the aziridine is activated at the Ni center via reduction. Here, we demonstrate that an Ni(II) azametallacycle, conventionally proposed in aziridine cross-coupling, is not an intermediate in the productive cross-coupling. Rather, stoichiometric organometallic and linear free energy relationship studies indicate that aziridine activation proceeds via Ni(I) oxidative addition, a previously unexplored elementary step.
Dongbang, Sun and Doyle, Abigail G.. "Ni/Photoredox-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors." Journal of the American Chemical Society, vol. 144, no. 43, Oct. 2022. https://doi.org/10.1021/jacs.2c09294
Dongbang, Sun, & Doyle, Abigail G. (2022). Ni/Photoredox-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors. Journal of the American Chemical Society, 144(43). https://doi.org/10.1021/jacs.2c09294
Dongbang, Sun, and Doyle, Abigail G., "Ni/Photoredox-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors," Journal of the American Chemical Society 144, no. 43 (2022), https://doi.org/10.1021/jacs.2c09294
@article{osti_1908536,
author = {Dongbang, Sun and Doyle, Abigail G.},
title = {Ni/Photoredox-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors},
annote = {Aziridines are readily available C(sp3) precursors that afford valuable β-functionalized amines upon ring opening. In this article, we report a Ni/photoredox methodology for C(sp3)–C(sp3) cross-coupling between aziridines and methyl/1°/2° aliphatic alcohols activated as benzaldehyde dialkyl acetals. Orthogonal activation modes of each alkyl coupling partner facilitate cross-selectivity in the C(sp3)–C(sp3) bond-forming reaction: the benzaldehyde dialkyl acetal is activated via hydrogen atom abstraction and β-scission via a bromine radical (generated in situ from single-electron oxidation of bromide), whereas the aziridine is activated at the Ni center via reduction. Here, we demonstrate that an Ni(II) azametallacycle, conventionally proposed in aziridine cross-coupling, is not an intermediate in the productive cross-coupling. Rather, stoichiometric organometallic and linear free energy relationship studies indicate that aziridine activation proceeds via Ni(I) oxidative addition, a previously unexplored elementary step.},
doi = {10.1021/jacs.2c09294},
url = {https://www.osti.gov/biblio/1908536},
journal = {Journal of the American Chemical Society},
issn = {ISSN 0002-7863},
number = {43},
volume = {144},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2022},
month = {10}}