Paper
Green Chemistry
The reaction worked well in all the cases and afforded the
desired products 2 in good to excellent yields (68–95%).
Styrenes 1 with an electron-donating group on the aromatic
ring appear to react faster and afford marginally higher yields
in comparison with those bearing an electron-withdrawing
group (Table 3, products 2b, 2c versus 2d–2i). However, the
reaction does not work with aliphatic alkenes, this is probably
because of the less stability of the radical intermediate formed
with aliphatic alkenes than that in the case of styrenes. More-
over, the greater stability of the radical formed at the α-posi-
tion of an aromatic or heteroaromatic ring plausibly governs
the high regioselectivity in the formation of product 2. The
efficacy of this reaction was also evaluated on a preparative
3 For recent reviews on visible-light-photoredox catalysis, see:
(a) M.-Y. Cao, X. Ren and Z. Lu, Tetrahedron Lett., 2015, 56,
3732; (b) J. Xiea, H. Jina, P. Xua and C. Zhu, Tetrahedron
Lett., 2014, 55, 36; (c) D. A. Nicewicz and T. M. Nguen, ACS
Catal., 2014, 4, 355; (d) X. Lang, X. Chen and J. Zhao,
Chem. Soc. Rev., 2014, 43, 473; (e) M. Reckenthäler and
A. G. Griesbeck, Adv. Synth. Catal., 2013, 355, 2727;
(f) D. Rovelli, M. Fagnoni and A. Albini, Chem. Soc. Rev.,
2013, 42, 97; (g) J. Hu, J. Wang, T. H. Nguyen and N. Zheng,
Beilstein J. Org. Chem., 2013, 9, 1977; (h) Y. Xi, H. Yia and
A. Lei, Org. Biomol. Chem., 2013, 11, 2387; (i) J. Xuan,
L.-Q. Lu, J.-R. Chen and W.-J. Xiao, Eur. J. Org. Chem., 2013,
6755; ( j) J. Xuan and W.-J. Xiao, Angew. Chem., Int. Ed.,
2012, 51, 6828; (k) J. W. Tucker and C. R. J. Stephenson,
J. Org. Chem., 2012, 77, 1617; (l) L. Shi and W. Xia, Chem.
Soc. Rev., 2012, 41, 7687; (m) Y.-Q. Zou, J.-R. Chen,
X.-P. Liu, L.-Q. Lu, R. L. Devis, K. A. Jorgensen and
W.-J. Xiao, Angew. Chem., Int. Ed., 2012, 51, 784; (n) S. Maity
and N. Zheng, Synlett, 2012, 1851; (o) J. M. R. Narayanam
and C. R. J. Stephenson, Chem. Soc. Rev., 2011, 40, 102.
4 For recent articles in support of the super oxide radical as
the oxidant, see: (a) A. K. Yadav and L. D. S. Yadav, Tetra-
hedron Lett., 2015, 56, 686; (b) A. K. Yadav and
L. D. S. Yadav, Tetrahedron Lett., 2015, 56, 6966;
scale (50 mmol). Thus, a mixture of CS (50.0 mmol, 3.5 mL),
2
2 3
Cs CO (1.0 equiv., 8.15 g) and MeOH (150 mL) was taken in a
closed flask and stirred at room temperature for 3 h. Then,
styrene (1a, 50.0 mmol, 5.78 g) and eosin Y (2 mol%, 0.652 g)
were added and the flask was open to air. The reaction mixture
was irradiated with green LEDs [2.50 W, λ = 535 nm] for 8 h in
open air under stirring at room temperature. Interestingly, the
product 2a was isolated in excellent yield (94%, 9.21 g) without
compromising the optimized reaction conditions.
(
5
c) A. K. Yadav and L. D. S. Yadav, Tetrahedron Lett., 2014,
5, 2065; (d) V. P. Srivastava, A. K. Yadav and L. D. S. Yadav,
Conclusion
In conclusion, we have disclosed a one-pot multicomponent
cyclization strategy for a highly regioselective synthesis of 1,3-
Tetrahedron Lett., 2014, 55, 1788; (e) C. L. Mathis,
B. M. Gist, C. K. Frederickson, K. M. Midkiff and
C. C. Marvin, Tetrahedron Lett., 2013, 54, 2101; (f) S. Zhu
and M. Rueping, Chem. Commun., 2012, 48, 11960;
(g) D. B. Freeman, L. Furst, A. G. Condie and
C. R. J. Stephenson, Org. Lett., 2012, 14, 94;
(h) D. A. DiRocco and T. Rovis, J. Am. Chem. Soc., 2012, 134,
8094; (i) G. Zhao, C. Yang, L. Guo, H. Sun, C. Chen and
W. Xia, Chem. Commun., 2012, 48, 2337; ( j) M. Rueping,
R. M. Koenigs, K. Poscharny, D. C. Fabry, D. Leonori and
C. Vila, Chem. – Eur. J., 2012, 18, 5170; (k) M. Rueping,
S. Zhu and R. M. Koenigs, Chem. Commun., 2011, 47, 8679;
oxathiolane-2-thiones from styrenes using CS , MeOH and
2
2 3
Cs CO in the presence of eosin Y as a photocatalyst at room
temperature. The salient features of the present protocol
include the step economy, organophotoredox catalysis and
2
utilization of clean resources, like air (O ) and visible light as
inexpensive, green and sustainable reagents, which make it a
superior alternative to the existing approaches to 1,3-oxathio-
lane-2-thiones.
(
2
l) M. Rueping, S. Zhu and R. M. Kónigs, Chem. Commun.,
011, 47, 12709; (m) J. Xuan, Y. Cheng, J. An, L.-Q. Lu,
Acknowledgements
We sincerely thank the SAIF, Punjab University, Chandigarh,
for providing spectra and one of the referees for his/her sug-
gestion for a significant improvement of the synthetic pro-
cedure. One of us (A. K. Y.) is grateful to the CSIR, New Delhi,
for the award of a Senior Research Fellowship (File no. (09/001
X.-X. Zhang and W.-J. Xiao, Chem. Commun., 2011, 47,
8337.
5 For biological activities of 1,3-oxathiolanes, see:
(a) M. T. Konieczny, W. Konieczny, M. Sabisz,
A. Skladanowski, R. Wakiec, E. Augustynowicz-Kopec and
Z. Zwolska, Chem. Pharm. Bull., 2007, 55, 817;
(0346)/2011-EMR-I)).
(
b) J. B. Jaquith, G. Villeneuve, P. Bureau and
A. Boudreault, Worldwide Patent, 2005012281, 2005;
c) T. Kikuchi, T. Mizukoshi and T. T. Niki, Japanese Patent,
002226463, 2002; Chem. Abstr., 2002, 137, 154930
(
2
Notes and references
1
R. A. Sheldon, Green Chem., 2007, 9, 1273 and references
cited therein.
For recent reviews, see: (a) J.-T. Yu and C. Pan, Chem.
Commun., 2016, 52, 2220; (b) A. Studer and D. P. Curran,
Nat. Chem., 2014, 6, 765; (c) C.-L. Sun and Z.-J. Shidx,
Chem. Rev., 2014, 114, 9219.
(d) L. D. S. Yadav, R. K. Tripathi, R. Dwivedi and H. Singh,
J. Agric. Foo. Chem., 1992, 40, 1700; (e) Y. Aizawa, T. Kanai,
K. Hasegawa, T. Yamaguchi, T. Iizuka, T. Iwaoka and
T. Yoshioka, J. Med. Chem., 1990, 33, 1491; (f) V. Nair,
B. Mathew, A. U. Vinod, J. S. Mathen, S. Ros, R. S. Menon,
R. L. Varma and R. Srinivas, Synthesis, 2003, 662;
2
Green Chem.
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