Skip to main content
Log in

Visible light-promoted alkylation of imines using potassium organotrifluoroborates

  • Communication
  • Published:
Photochemical & Photobiological Sciences Aims and scope Submit manuscript

A Correction to this article was published on 01 September 2018

This article has been updated

Abstract

A mild, redox-neutral, alkylation of imines with potassium alkyl-trifluoroborates is described. The reaction proceeds under photo-redox conditions at ~30 °C with primary, secondary, and tertiary alkyltrifluoroborates, leading to alkylation products in moderate to good yield in most cases. Aryl-, vinyl-, and cyclopropyltrifluoroborates failed to react under the reported conditions.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Change history

References

  1. E. Marcantoni and M. Petrini, Lewis acid promoted addition reactions of organometallic compounds, Compr. Org. Synth., 2014, 1, 344–364, (2nd Ed.)

    Article  CAS  Google Scholar 

  2. K.-i. Yamada and K. Tomioka, Copper-catalyzed asymmetric alkylation of imines with dialkylzinc and related reactions, Chem. Rev., 2008, 108, 2874–2886

    Article  CAS  Google Scholar 

  3. R. Bloch, Additions of organometallic reagents to C=N Bonds: Reactivity and selectivity, Chem. Rev., 1998, 98, 1407–1438.

    Article  CAS  Google Scholar 

  4. Recently, however, addition of alkyllithiums and Grignard reagents to imines in water under air has been reported: G. Dilauro, M. Dell'Aera, P. Vitale, V. Capriati and F. M. Perena, Unprecedented nucleophilic additions of highly polar organometallic compounds to imines and nitriles using water as a non-innocent reaction medium, Angew. Chem., Int. Ed., 2017, 56, 10200–10203.

  5. J. Tauber, D. Imbri and T. Opatz, Radical addition to iminium ions and cationic heterocycles, Molecules, 2014, 19, 16190–16222

    Article  Google Scholar 

  6. R. Cannella, A. Clerici, N. Pastori, E. Regolini and O. Porta, One-pot four-component reaction: Aqueous TiCl3/PhN2+-mediated alkyl radical addition to imines generated in situ, Org. Lett., 2005, 7, 645–648

    Article  CAS  Google Scholar 

  7. G. K. Friestad, Addition of carbon-centered radicals to imines and related compounds, Tetrahedron, 2001, 57, 5461–5496.

    Article  CAS  Google Scholar 

  8. M. H. Shaw, J. Twilton and D. W. MacMillan, Photoredox catalysis in organic chemistry, J. Org. Chem., 2016, 81, 6898–6926

    Article  CAS  Google Scholar 

  9. C. K. Prier, D. A. Rankic and D. W. MacMillan, Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis, Chem. Rev., 2013, 113, 5322–5363.

    Article  CAS  Google Scholar 

  10. N. A. Romero and D. A. Nicewicz, Organic photoredox catalysis, Chem. Rev., 2016, 116, 10075–10166.

    Article  CAS  Google Scholar 

  11. L. Chenneberg, C. Lévêque, V. Corcé, A. Baralle, J.-P. Goddard, C. Ollivier and L. Fensterbank, SingleElectron-Transfer Oxidation of Trifluoroborates and Silicates with Organic Reagents: A Comparative Study, Synlett, 2016, 27, 731–735.

    Article  CAS  Google Scholar 

  12. Y. Yasu, T. Koike and M. Akita, Visible light-induced selective generation of radicals from organoborates by photoredox catalysis, Adv. Synth. Catal., 2012, 354, 3414–3420.

    Article  CAS  Google Scholar 

  13. T. Chinzei, K. Miyazawa, Y. Yasu, T. Koike and M. Akita, Redox-economical radical generation from organoborates and carboxylic acids by organic photoredox catalysis, RSC Adv., 2015, 5, 21297–21300.

    Article  CAS  Google Scholar 

  14. Y. Li, K. Miyazawa, T. Koike and M. Akita, Alkyl- and arylthioalkylation of olefins with organotrifluoroborates by photoredox catalysis, Org. Chem. Front., 2015, 2, 319–323.

    Article  CAS  Google Scholar 

  15. D. N. Primer, I. Karakaya, J. C. Tellis and G. A. Molander, Single-electron transmetalation: an enabling technology for secondary alkylboron cross-coupling, J. Am. Chem. Soc., 2015, 137, 2195–2198.

    Article  CAS  Google Scholar 

  16. G. A. Molander, Organotrifluoroborates: Another branch of the mighty oak, J. Org. Chem., 2015, 80, 7837–7848

    Article  CAS  Google Scholar 

  17. S. Darses and J.-P. Genet, Potassium trifluoro (organo)borates: New perspectives in organic chemistry, Eur. J. Org. Chem., 2003, 4313–4327.

    Google Scholar 

  18. D. E. Carrera, The acid promoted Petasis reaction of organotrifluoroborates with imines and enamines, Chem. Commun., 2017, 53, 11185–11188

    Article  CAS  Google Scholar 

  19. S. Lee, W. L. Lee and J. Yun, Rhodium-catalyzed addition of alkyltrifluoroborate salts to imines, Adv. Synth. Catal., 2015, 357, 2219–2222

    Article  CAS  Google Scholar 

  20. R. Batey and T. Ramadhar, Allylation of imines and their derivatives with organoboron reagents: Stereocontrolled synthesis of homoallylic amines, Synthesis, 2011, 1321–1346

    Google Scholar 

  21. P. Tian, H.-Q. Dong and G.-Q. Lin, Rhodium-catalyzed asymmetric arylation, ACS Catal., 2012, 2, 95–119

    Article  CAS  Google Scholar 

  22. Y. Luo, H. B. Hepburn, N. Chotsaeng and H. W. Lam, Enantioselective rhodium-catalyzed nucleophilic allylation of cyclic imines with allylboron reagents, Angew. Chem., Int. Ed., 2012, 51, 8309–8313

    Article  CAS  Google Scholar 

  23. K. Brak and J. A. Ellman, Asymmetric Rh(I)-catalyzed addition of MIDA boronates to N-tert-butanesulfinyl aldimines: Development and comparison to trifluoroborates, J. Org. Chem., 2010, 75, 3147–3150.

    Article  CAS  Google Scholar 

  24. V. Corce, L. M. Chamoreau, E. Derat, J. P. Goddard, C. Ollivier and L. Fensterbank, Silicates as latent alkyl radical precursors: Visible-light photocatalytic oxidation of hypervalent bis-catecholato silicon compounds, Angew. Chem., Int. Ed., 2015, 54, 11414–11418

    Article  CAS  Google Scholar 

  25. N. R. Patel, C. B. Kelly, A. P. Siegenfeld and G. A. Molander, Mild, redox-neutral alkylation of imines enabled by an organic photocatalyst, ACS Catal., 2017, 7, 1766–1770.

    Article  CAS  Google Scholar 

  26. H. H. Zhang and S. Yu, Radical alkylation of imines with 4-alkyl-1,4-dihydropyridines enabled by photoredox/ Bronsted acid cocatalysis, J. Org. Chem., 2017, 82, 9995–10006.

    Article  CAS  Google Scholar 

  27. M. S. Lowry, J. I. Goldsmith, J. D. Slinker, R. Rohl, R. A. Pascal, G. G. Malliaras and S. Bernhard, Single-layer electroluminescent devices and photoinduced hydrogen production from an ionic iridium(III) complex, Chem. Mater., 2005, 17, 5712–5719.

    Article  CAS  Google Scholar 

  28. Unless otherwise noted, reduction potentials are reported vs. the saturated calomel electrode (SCE) in acetonitrile.

  29. M. Nakajima, E. Fava, S. Loescher, Z. Jiang and M. Rueping, Photoredox-catalyzed reductive coupling of aldehydes, ketones, and imines with visible light, Angew. Chem., Int. Ed., 2015, 54, 8828–8832.

    Article  CAS  Google Scholar 

  30. F. A. Carey and R. J. Sundberg, Advanced Organic Chemistry, Springer, New York, 4th edn, 2000, pp. 695–697.

    Google Scholar 

  31. CRC Handbook of Chemistry and Physics, ed. D.R. Lide, CRC Press, Boca Raton, Florida, 74th edn, 1993, p. 9–136.

    Google Scholar 

  32. Generation of the dichloromethyl radical has been accomplished using peroxide initiators: Y. Tian and Z.-Q. Liu, Metal-free radical cascade dichloromethylation of activated alkenes using CH2Cl2: Highly selective activation of the C-H bond, RSC Adv., 2014, 4, 64855–64859.

  33. The reduction potential of the similar N-methylanilinyl radical has been reported to be -0.78 V. See: M. Jonsson, D. D. M. Wayner and J. Lusztyk, Redox and acidity properties of alkyl- and arylamine radical cations and the corresponding aminyl radicals, J. Phys. Chem., 1996, 100, 17539–17543.

  34. M. D. Kärkäs, B. S. Matsuura and C. R. J. Stephenson, Enchained by visible light-mediated photoredox catalysis, Science, 2015, 349, 1285–1286.

    Article  Google Scholar 

  35. M. A. Cismesia and T. P. Yoon, Characterizing chain processes in visible light photoredox catalysis, Chem. Sci., 2015, 6, 5426–5434.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund (58270-UR1) for support of this research. Additional support was provided by an SC-INBRE grant from the National Institute of General Medical Sciences (P20 GM103499) and the Winthrop University Research Council. The authors would also like to thank Michael Walla and William Cotham of the University of South Carolina Department of Chemistry and Biochemistry for high resolution mass spectrometry analysis.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to James M. Hanna Jr..

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Plasko, D.P., Jordan, C.J., Ciesa, B.E. et al. Visible light-promoted alkylation of imines using potassium organotrifluoroborates. Photochem Photobiol Sci 17, 534–538 (2018). https://doi.org/10.1039/c8pp00061a

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1039/c8pp00061a

Navigation