ChemComm
Communication
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`
Chem. Front., 2018, 5, 1406; (h) V. Quint, N. Chouchene, M. Askri,
Scheme 4 Plausible mechanism.
´
J. Lalevee, A.-C. Gaumont and S. Lakhdar, Org. Chem. Front., 2019,
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On the basis of the above experimental results and previous
reports,6 a plausible mechanism is proposed as shown in
Scheme 4. We reasoned that an alkyl radical would be generated
from Katritzky salt 1 via a reductive single electron transfer by
visible-light excited Ir(III) species. This alkyl radical would then
capture sulfur dioxide, giving rise to alkylsulfonyl radical inter-
mediate. Subsequently, this alkylsulfonyl radical intermediate
would be trapped by silyl enol ether 2, resulting in the formation
of radical intermediate A. With the assistance of Ir(IV), radical
intermediate A would be oxidized to carbocation B. In the
presence of base, desilylation would occur to provide the desired
ketone product 3.
5 For selected examples, see: (a) D. Zheng, Y. An, Z. Li and J. Wu,
Angew. Chem., Int. Ed., 2014, 53, 2451; (b) D. Zheng, J. Yu and J. Wu,
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G. Qiu, Chem. Commun., 2019, 55, 2214; ( f ) S. Ye, Y. Li, J. Wu and
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(l) F.-S. He, Y. Wu, X. Li, H. Xia and J. Wu, Org. Chem. Front., 2019,
6, 1873.
In conclusion, we have developed an efficient route to
dialkyl sulfones by using Katritzky salts as the alkyl radical
precursors with the insertion of sulfur dioxide under photo-
redox catalysis. This transformation proceeds through a radical
process using silyl enol ethers as the radical trapper, leading to
diverse dialkyl sulfones in good yields under the visible-light
induced conditions. During the conversion, the generation of
alkyl radical from Katritzky salt is the key under photocatalysis.
Financial support from National Natural Science Foundation
of China (No. 21871053 and 21532001) is gratefully acknowledged.
6 For reviews, see: (a) P. Bisseret and N. Blanchard, Org. Biomol. Chem.,
2013, 11, 5393; (b) A. S. Deeming, E. J. Emmett, C. S. Richards-Taylor
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7 (a) Y. Li, D. Zheng, Z. Li and J. Wu, Org. Chem. Front., 2016, 3, 574;
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8 (a) T. Liu, Y. Li, L. Lai, J. Cheng, J. Sun and J. Wu, Org. Lett., 2018,
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9 X. Wang, M. Yang, W. Xie, X. Fan and J. Wu, Chem. Commun., 2019,
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Conflicts of interest
There are no conflicts to declare.
10 (a) X. Gong, J. Chen, J. Liu and J. Wu, Org. Chem. Front., 2017,
4, 2221; (b) N.-W. Liu, S. Liang and G. Manolikakes, Adv. Synth.
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Notes and references
1 (a) J. M. J. Nolsøe, M. Aursnes, J. E. Tungen and T. V. Hansen, J. Org.
Chem., 2015, 80, 5377; (b) S. Sowmiah, J. M. S. S. Esperança,
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14964 | Chem. Commun., 2019, 55, 14962--14964
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