RSC Advances
Paper
Taking into account all the experimental evidences, we
propose that under UV light irradiation, benzyl alcohol in the
presence of DMSO is transformed to the corresponding radical
M. Wellard, J. Jia, L. Jing, Y. Huang, J. P. Blinco, H. Wu
and H. Y. Zhu, ACS Catal., 2016, 6, 3580–3588; (f)
C. J. Weiss, P. Das, D. L. Miller, M. L. Helm and
A. M. Appel, ACS Catal., 2014, 4, 2951–2958; (g) Y. Yuan,
N. Yan and P. J. Dyson, Inorg. Chem., 2011, 50, 11069–
11074; (h) S. Gowrisankar, H. Neumann, D. Goerdes,
K. Thurow, H. Jiao and M. Beller, Chem.–Eur. J., 2013, 19,
15979–15984; (i) Z. Guo, B. Liu, Q. Zhang, W. Deng,
Y. Wang and Y. Yang, Chem. Soc. Rev., 2014, 43, 3480–3524.
3 (a) G. Tojo and M. I. Fern ´a ndez, Oxidation of Alcohols to
Aldehydes and Ketones: A Guide to Current Common Practice,
Springer Science, NewYork, 2006; (b) H. B. Friedrich,
Platinum Met. Rev., 1999, 43, 94–102; (c) K. Alfonsi,
J. Colberg, P. J. Dunn, T. Fevig, S. Jennings, T. A. Johnson,
H. P. Kleine, C. Knight, M. A. Nagy, D. A. Perry and
M. Stefaniak, Green Chem., 2008, 10, 31–36; (d) K. Omura
and D. Swern, Tetrahedron, 1978, 34, 1651–1660; (e)
K. E. Ptzner and J. G. Moffatt, J. Am. Chem. Soc., 1963, 85,
3027–3028; (f) J. R. Parikh and W. V. E. Doering, J. Am.
Chem. Soc., 1967, 89, 5505–5507; (g) J. D. Albright and
L. Goldman, J. Am. Chem. Soc., 1965, 87, 4214–4216.
cation (A) (vide supra) with simultaneous reduction of O (from
2
air) to generate oxidant superoxide radical anion. The radical
cation (A) then reacted with the superoxide anion to generate
peroxide radical which abstract hydrogen atom from interme-
diate B to furnish the desired product (Scheme 5). We believe
2
that DMSO (ref. 6b) is generated as byproduct in the reaction
sequence which is generated aer the oxidation of DMSO by the
in situ-generated H O . The byproduct DMSO is removed
2
2
2
during the aqueous workup of the reaction mixture (Fig. S23,
ESI†).
Conclusions
In conclusion, the present study demonstrates the important
role of alcohols themselves as electron donors for their selective
oxidative transformations to the corresponding carbonyl
compounds in absence of any metal/oxidant and external
photosensitizer. The photopromoted oxidation exhibited wide
substrate scope and especially high reactivity toward aromatic,
alicyclic, and heteroaromatic alcohols. The practical application
of the approach has been demonstrated by carrying out selective
oxidation of steroid (cholesterol), which is a key component for
many pharmaceuticals.
4 (a) W. Adam, C. R. Saha-Moller and P. A. Ganeshpure, Chem.
Rev., 2001, 101, 3499–3548; (b) B. Karimi, A. Biglari,
J. H. Clark and V. Budarin, Angew. Chem., Int. Ed., 2007, 46,
7210–7213; (c) X. Zhang, X. Fu, Y. Zhang, Y. Zhu and
J. Yang, Catal. Lett., 2016, 146, 945–950; (d) H. Watanabe,
S. Asano, S. Fujita, H. Yoshida and M. Arai, ACS Catal.,
2
015, 5, 2886–2894.
Conflicts of interest
5
(a) R. Liu, X. Liang, C. Dong and X. Hu, J. Am. Chem. Soc.,
2004, 126, 4112–4113; (b) B. Karimi, A. Biglari, J. H. Clark
and V. Budarin, Angew. Chem., Int. Ed., 2007, 46, 7210–
There are no conicts to declare.
7
2
213; (c) L. Tebben and A. Studer, Angew. Chem., Int. Ed.,
011, 50, 5034–5068; (d) M. S. Laeini and A. Shaabani,
Acknowledgements
V. B. and M. K. are thankful to Science and Engineering
Research Board (SERB), New Delhi (ref. no. CRG/2018/001274)
and (ref no. EMR/2016/003473) for nancial support respec-
tively. P. K. W. is thankful to UGC for Senior Research Fellow-
ship (SRF). We are also thankful to UGC (New Delhi, India) for
the “University with Potential for Excellence” (UPE) project.
ChemistrySelect, 2017, 2, 9084–9087; (e) S. Wertz and
A. Studer, Green Chem., 2013, 15, 3116–3134; (f) Y. Yan,
X. Tong, K. Wang and X. Bai, Catal. Commun., 2014, 43,
112–115; (g) J. Zhu, X. J. Zhao, P. C. Wang and M. Lu,
Chem. Lett., 2013, 42, 1505–1507; (h) X. Wang, R. Liu, Y. Jin
and X. Liang, Chem.–Eur. J., 2008, 14, 2679–2685; (i) X. He,
Z. Shen, W. Mo, N. Sun, B. Hu and X. Hu, Adv. Synth.
Catal., 2009, 351, 89–92.
(a) W. Huang, B. C. Ma, H. Lu, R. Li, L. Wang, K. Landfester
and K. A. I. Zhang, ACS Catal., 2017, 7, 5438–5442; (b)
W. Schilling, D. Riemer, Y. Zhang, N. Hatami and S. Das,
ACS Catal., 2018, 8, 5425–5430; (c) F. Su, S. C. Mathew,
G. Lipner, X. Fu, M. Antonietti, S. Blechert and X. Wang, J.
Am. Chem. Soc., 2010, 132, 16299–16301; (d) K. Walsh,
H. F. Sneddon and C. J. Moody, Org. Lett., 2014, 16, 5224–
5227; (e) Y. Wang, X. Wang and M. Antonietti, Angew.
Chem., Int. Ed., 2012, 51, 68–89; (f) Y. Chen, J. Zhang,
M. Zhang and X. Wang, Chem. Sci., 2013, 4, 3244–3248; (g)
W. Zhang, A. Bariotaki, I. Smonou and F. Hollmann, Green
Chem., 2017, 19, 2096–2100.
Notes and references
6
1
(a) J. E. Backvall, Modern Oxidation Methods, WileyꢁVCH,
New York, 2004; (b) J. Kochi and R. Sheldon, Metal
Catalyzed Oxidations of Organic Compounds, Academic
Press, New York, 1981; (c) T. Mallat and A. Baiker, Chem.
Rev., 2004, 104, 3037–3058; (d) S. Caron, R. W. Dugger,
S. G. Ruggeri, J. A. Ragan and D. H. B. Ripin, Chem. Rev.,
2006, 106, 2943–2989.
2
(a) R. Ray, S. Chandra, D. Maiti and G. K. Lahiri, Chem.–Eur.
J., 2016, 22, 8814–8822; (b) J. N. Jaworski, S. D. McCann,
I. A. Guzei and S. S. Stahl, Angew. Chem., Int. Ed., 2017, 56,
3605–3610; (c) H. Su, K. X. Zhang, B. Zhang, H. H. Wang,
Q. Y. Yu, X. H. Li, M. Antonietti and J. S. Chen, J. Am.
Chem. Soc., 2017, 139, 811–818; (d) B. Xu, J. P. Lumb and
B. A. Arndtsen, Angew. Chem., Int. Ed., 2015, 54, 4208–4211;
7 V. J. Traynelis and W. L. Hergenrother, J. Am. Chem. Soc.,
1964, 86, 298–299.
8 (a) N. Romero and D. A. Nicewicz, Chem. Rev., 2016, 116,
10075–10166; (b) S. Ghosh, N. A. Kouame, L. Ramos,
(
e) S. Zavahir, Q. Xiao, S. Sarina, J. Zhao, S. Bottle,
36202 | RSC Adv., 2019, 9, 36198–36203
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