Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Boron-catalysed hydrogenolysis of unactivated C(aryl)–C(alkyl) bonds


The hydrogenolysis of C–C bonds is one of the most important processes in the petroleum industry. These transformations typically rely on heterogeneous catalysts and take place at high temperatures and high pressures with limited selectivity. Employing homogeneous transition metal catalysts, while allowing the hydrogenolysis of C–C bonds to proceed under much milder conditions, is only suitable for substrates containing strained C–C bonds or directing groups. Here we report that a borenium complex can catalyse the selective hydrogenolysis of unstrained C(aryl)–C(alkyl) bonds of alkylarenes in the absence of directing groups at ambient temperature, affording the corresponding alkanes and arenes. Mechanistic studies suggest a reaction pathway that involves a synergistic activation of dihydrogen by the borenium complex and alkylarenes, followed by retro-Friedel–Crafts reaction to cleave the C(aryl)–C(alkyl) bonds. The synthetic utility of this protocol is demonstrated by the conversion of post-consumer polystyrene into valuable benzene and phenylalkanes with mass recovery rates above 90%.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Different approaches to hydrodealkylation.
Fig. 2: Substrate scope of hydrodealkylation.
Fig. 3: Mechanism investigation of the hydrogenolysis of 6.
Fig. 4: Hydrogenolysis of polystyrene with 1a as catalyst.

Data availability

All data supporting the findings of this study are available within the Article and its Supplementary Information or from the corresponding authors upon reasonable request.


  1. Hsu, C. S. & Robinson, P. R. Petroleum Science and Technology (Springer, 2019).

  2. Ancheyta, J. & Speight, J. G. Hydroprocessing of Heavy Oils and Residua (CRC Press, 2007).

  3. Olah, G. A. & Molnár, Á. Hydrocarbon Chemistry 2nd edn (Wiley, 2003).

  4. Ellis, L. D. et al. Chemical and biological catalysis for plastics recycling and upcycling. Nat. Catal. 4, 539–556 (2021).

    Article  CAS  Google Scholar 

  5. Vollmer, I. et al. Beyond mechanical recycling: giving new life to plastic waste. Angew. Chem. Int. Ed. 59, 15402–15423 (2020).

    Article  CAS  Google Scholar 

  6. To, C. T. & Chan, K. S. Catalytic carbon–carbon sigma-bond hydrogenolysis. Tetrahedron Lett. 57, 4664–4669 (2016).

    Article  CAS  Google Scholar 

  7. Perthuisot, C. & Jones, W. D. Catalytic hydrogenolysis of an aryl–aryl carbon–carbon bond with a rhodium complex. J. Am. Chem. Soc. 116, 3647–3648 (1994).

    Article  CAS  Google Scholar 

  8. Bart, S. & Chirik, P. J. Selective, catalytic carbon−carbon bond activation and functionalization promoted by late transition metal catalysts. J. Am. Chem. Soc. 125, 886–887 (2003).

    Article  CAS  Google Scholar 

  9. To, C. T., Choi, K. S. & Chan, K. S. Catalytic carbon–carbon σ-bond hydrogenation with water catalyzed by rhodium porphyrins. J. Am. Chem. Soc. 134, 11388–11391 (2012).

    Article  CAS  Google Scholar 

  10. Liou, S.-Y., van der Boom, M. E. & Milstein, D. Catalytic selective cleavage of a strong C–C single bond by rhodium in solution. Chem. Commun. 687–688 (1998).

  11. Chen, K. et al. Reductive cleavage of the Csp2–Csp3 bond of secondary benzyl alcohols: rhodium catalysis directed by N-containing groups. Angew. Chem. Int. Ed. 51, 9851–9855 (2012).

    Article  CAS  Google Scholar 

  12. Zhu, J., Wang, J. & Dong, G. Catalytic activation of unstrained C(aryl)–C(aryl) bonds in 2,2′-biphenols. Nat. Chem. 11, 45–51 (2019).

    Article  CAS  Google Scholar 

  13. Zhu, J., Chen, P.-h, Lu, G., Liu, P. & Dong, G. Ruthenium-catalyzed reductive cleavage of unstrained aryl–aryl bonds: reaction development and mechanistic study. J. Am. Chem. Soc. 141, 18630–18640 (2019).

    Article  CAS  Google Scholar 

  14. Zhu, J., Xue, Y., Zhang, R., Ratchford, B. L. & Dong, G. Catalytic activation of unstrained C(Aryl)–C(Alkyl) bonds in 2,2′-methylenediphenols. J. Am. Chem. Soc. 144, 3242–3249 (2022).

    Article  CAS  Google Scholar 

  15. Power, P. P. Main-group elements as transition metals. Nature 463, 171–177 (2010).

    Article  CAS  Google Scholar 

  16. Melen, R. L. Frontiers in molecular p-block chemistry: from structure to reactivity. Science 363, 479–484 (2019).

    Article  CAS  Google Scholar 

  17. Legaré, M.-A., Pranckevicius, C. & Braunschweig, H. Metallomimetic chemistry of boron. Chem. Rev. 119, 8231–8261 (2019).

    Article  Google Scholar 

  18. Franck, H.-G. & Stadelhofer, J. W. Industrial Aromatic Chemistry (Springer, 1988).

  19. Wiesenfeldt, M. P., Nairoukh, Z., Dalton, T. & Glorius, F. Selective arene hydrogenation for direct access to saturated carbo- and heterocycles. Angew. Chem. Int. Ed. 58, 10460–10476 (2019).

    Article  CAS  Google Scholar 

  20. Gozin, M., Weisman, A., Ben-David, Y. & Milstein, D. Activation of a carbon–carbon bond in solution by transition-metal insertion. Nature 364, 698–701 (1993).

    Article  Google Scholar 

  21. Welch, G. C., San Juan, R., Masuda, J. D. & Stephan, D. W. Reversible, metal-free hydrogen activation. Science 314, 1124–1126 (2006).

    Article  CAS  Google Scholar 

  22. Stephan, D. W. & Erker, G. Frustrated Lewis pair chemistry: development and perspectives. Angew. Chem. Int. Ed. 54, 6400–6441 (2015).

    Article  CAS  Google Scholar 

  23. Stephan, D. W. The broadening reach of frustrated Lewis pair chemistry. Science 354, aaf7229 (2016).

    Article  Google Scholar 

  24. Farrell, J. M., Hatnean, J. A. & Stephan, D. W. Activation of hydrogen and hydrogenation catalysis by a borenium cation. J. Am. Chem. Soc. 134, 15728–15731 (2012).

    Article  CAS  Google Scholar 

  25. Farrell, J. M., Posaratnanathan, R. T. & Stephan, D. W. A family of N-heterocyclic carbene-stabilized borenium ions for metal-free imine hydrogenation catalysis. Chem. Sci. 6, 2010–2015 (2015).

    Article  CAS  Google Scholar 

  26. Welch, G. C. & Stephan, D. W. Facile heterolytic cleavage of dihydrogen by phosphines and boranes. J. Am. Chem. Soc. 129, 1880–1881 (2007).

    Article  CAS  Google Scholar 

  27. Stephan, D. W. Diverse uses of the reaction of frustrated Lewis pair (FLP) with hydrogen. J. Am. Chem. Soc. 143, 20002–20014 (2021).

    Article  CAS  Google Scholar 

  28. Rokob, T. A., Hamza, A., Stirling, A., Soós, T. & Pápai, I. Turning frustration into bond activation: a theoretical mechanistic study on heterolytic hydrogen splitting by frustrated Lewis pairs. Angew. Chem. Int. Ed. 47, 2435–2438 (2008).

    Article  CAS  Google Scholar 

  29. Grimme, S., Kruse, H., Goerigk, L. & Erker, G. The mechanism of dihydrogen activation by frustrated Lewis pairs revisited. Angew. Chem. Int. Ed. 49, 1402–1405 (2010).

    Article  CAS  Google Scholar 

  30. Olah, G. A. & Prakash, G. K. S. (eds). Carbocation Chemistry (Wiley, 2004).

  31. MacKnight, E. & McClelland, R. A. A photochemical retro-Friedel–Crafts alkylation. Rapid rearrangement of cyclohexadienyl cations. Can. J. Chem. 74, 2518–2527 (1996).

    Article  CAS  Google Scholar 

  32. Mahdi, T., Heiden, Z. M., Grimme, S. & Stephan, D. W. Metal-free aromatic hydrogenation: aniline to cyclohexyl-amine derivatives. J. Am. Chem. Soc. 134, 4088–4091 (2012).

    Article  CAS  Google Scholar 

  33. Liu, Y., Dong, W., Li, Z. H. & Wang, H. Methane activation by a borenium complex. Chem 7, 1843–1851 (2021).

    Article  CAS  Google Scholar 

  34. Liu, Y., Su, B., Dong, W., Li, Z. H. & Wang, H. Structural characterization of a boron(III) η2σ-silane-complex. J. Am. Chem. Soc. 141, 8358–8363 (2019).

    Article  CAS  Google Scholar 

  35. Houghton, A. Y. & Autrey, T. Calorimetric study of the activation of hydrogen by tris(pentafluorophenyl)borane and trimesitylphosphine. J. Phys. Chem. A 121, 8785–8790 (2017).

    Article  CAS  Google Scholar 

  36. Zhao, Y. & Truhlar, D. G. A new local density functional for main-group thermochemistry, transition metal bonding, thermochemical kinetics, and noncovalent interactions. J. Chem. Phys. 125, 194101 (2006).

    Article  Google Scholar 

  37. Maul, J. et al. in Ullmann’s Encyclopedia of Industrial Chemistry (Wiley, 2012);

  38. Maharana, T., Negi, Y. S. & Mohanty, B. Recycling of polystyrene. Polym. Plast. Tech. Eng. 46, 729–736 (2007).

    Article  CAS  Google Scholar 

  39. Jing, Y. et al. Towards the circular economy: converting aromatic plastic waste back to arenes over a Ru/Nb2O5 catalyst. Angew. Chem. Int. Ed. 60, 5527–5535 (2021).

    Article  CAS  Google Scholar 

  40. Wang, J. et al. Recycling benzene and ethylbenzene from in-situ catalytic fast pyrolysis of plastic wastes. Energ. Convers. Manag. 200, 112088 (2019).

    Article  CAS  Google Scholar 

  41. González-Marcos, M. P., Fuentes-Ordóñez, E. G., Salbidegoitia, J. A. & González-Velasco, J. R. Optimization of supports in bifunctional supported Pt catalysts for polystyrene hydrocracking to liquid fuels. Top. Catal. 64, 224–242 (2021).

    Article  Google Scholar 

  42. Fuentes-Ordóñez, E. G., Salbidegoitia, J. A., González-Marcos, M. P. & González-Velasco, J. R. Mechanism and kinetics in catalytic hydrocracking of polystyrene in solution. Polym. Degrad. Stabil. 124, 51–59 (2016).

    Article  Google Scholar 

  43. Wang, Y., Chen, W., Lu, Z., Li, Z. H. & Wang, H. Metal-free HB(C6F5)2-catalyzed hydrogenation of unfunctionalized olefins and mechanism study of borane-mediated σ-bond metathesis. Angew. Chem. Int. Ed. 52, 7496–7499 (2013).

    Article  CAS  Google Scholar 

  44. Kocal, J. A., Vora, B. V. & Imai, T. Production of linear alkylbenzenes. Appl. Catal. A. 221, 295–301 (2001).

    Article  CAS  Google Scholar 

Download references


We thank G. Tang, L. Wang and Y. Zhao for their assistance with GC–MS, NMR and inductively coupled plass mass spectrometry experiments. Financial support for this work was provided by the National Natural Science Foundation of China (21871051 (H.W.), 21873019 (Z.H.L.) and 22071027 (H.W.)), the Shanghai Science and Technology Committee (19DZ2270100) and Fudan University.

Author information

Authors and Affiliations



H.W. conceived the research and designed the project. Y.X. and Y.L. optimized the reaction conditions. Y.X. studied the substrate scope and carried out experimental mechanism investigation. Y.Y studied the hydrogenolysis of polystyrene. Z.H.L. undertook the density functional theory calculations. H.W. wrote the manuscript with input from all authors. All authors analysed the results and commented on the manuscript.

Corresponding author

Correspondence to Huadong Wang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Catalysis thanks Ning Yan and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–140, Tables 1–25 and Methods.

Supplementary Data 1

Computational data.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Xu, Y., Yang, Y., Liu, Y. et al. Boron-catalysed hydrogenolysis of unactivated C(aryl)–C(alkyl) bonds. Nat Catal 6, 16–22 (2023).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing