ChemComm
Communication
3 For reviews on C–H bond activation using Ru catalysts, see:
(a) L. Ackermann, R. Vicente and A. R. Kapdi, Angew. Chem., Int.
Ed., 2009, 48, 9792; (b) L. Ackermann and R. Vicente, Top. Curr.
Chem., 2010, 292, 211; (c) L. Ackermann, Chem. Commun., 2010,
46, 4866; (d) P. B. Arockiam, C. Bruneau and P. H. Dixneuf, Chem.
Rev., 2012, 112, 5879.
4 (a) T. Ueyama, S. Mochida, T. Fukutani, K. Hirano, T. Satoh and
M. Miura, Org. Lett., 2011, 13, 706; (b) L. Ackermann and J. Pospech,
Org. Lett., 2011, 13, 4153; (c) K. Padala and M. Jeganmohan, Org.
Lett., 2011, 13, 6144; (d) K. Padala and M. Jeganmohan, Org. Lett.,
2012, 14, 1134; (e) Y. Hashimoto, T. Ortloff, K. Hirano, T. Satoh,
C. Bolm and M. Miura, Chem. Lett., 2012, 41, 151.
Scheme 1 Regioselectivity between rhodium vs. ruthenium catalysts.
5 (a) S. Oi, K. Sakai and Y. Inoue, Org. Lett., 2005, 7, 4009;
(b) L. Ackermann, Org. Lett., 2005, 7, 3123; (c) S. Oi, R. Funayama,
T. Hattori and Y. Inoue, Tetrahedron, 2008, 64, 6051.
6 (a) K. Cheng, B. B. Yao, J. L. Zhao and Y. H. Zhang, Org. Lett., 2008,
10, 5309; (b) Y. Hashimoto, K. Hirano, T. Satoh, F. Kakiuchi and
M. Miura, Org. Lett., 2012, 14, 2058.
Scheme 2 Kinetic isotope experiment.
7 (a) T. Kochi, S. Urano, H. Seki, E. Mizushima, M. Sato and
F. Kakiuchi, J. Am. Chem. Soc., 2009, 131, 2792; (b) T. Kochi,
A. Tazawa, K. Honda and F. Kakiuchi, Chem. Lett., 2011, 40, 1018.
8 (a) V. S. Thirunavukkarasu, J. Hubrich and L. Ackermann, Org. Lett.,
2012, 14, 4210; (b) Y. Yang, Y. Lin and Y. Rao, Org. Lett., 2012, 14, 2874.
9 (a) L. Ackermann, A. V. Lygin and N. Hofmann, Angew. Chem., Int.
Ed., 2011, 50, 6379; (b) L. Ackermann, L. Wang and A. V. Lygin,
Chem. Sci., 2012, 3, 177; (c) L. Ackermann, J. Pospech, K. Graczyk
and K. Rauch, Org. Lett., 2012, 14, 930; (d) Y. Hashimoto, T. Ueyama,
T. Fukutani, K. Hirano, T. Satoh and M. Miura, Chem. Lett., 2011,
40, 1165; (e) L. Ackermann, A. V. Lygin and N. Hofmann, Org. Lett.,
2011, 13, 3278; ( f ) L. Ackermann, L. Wang, R. Wolfram and
A. V. Lygin, Org. Lett., 2012, 14, 728.
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D.-Q. Yu, J. Nat. Prod., 2009, 72, 966; (c) B. M. Trost, O. R. Thiel and
H.-C. Tsui, J. Am. Chem. Soc., 2002, 124, 11616.
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P. Knochel, Org. Lett., 2003, 5, 2111; (b) Y. Kiyotsuka, H. P. Acharya,
Y. Katayama, T. Hyodo and Y. Kobayashi, Org. Lett., 2008, 10, 1719.
12 (a) C. C. Price, Org. React., 1946, 3, 1; (b) M. Niggemann and
M. J. Meel, Angew. Chem., Int. Ed., 2010, 49, 3684.
13 (a) M. A. Kacprzynski, T. L. May, S. A. Kazane and A. H. Hoveyda,
Angew. Chem., Int. Ed., 2007, 46, 4554; (b) H. Ohmiya, Y. Makida,
T. Tanaka and M. Sawamura, J. Am. Chem. Soc., 2008, 130, 17276;
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14 S. Oi, Y. Tanaka and Y. Inoue, Organometallics, 2006, 25, 4773.
15 A. S. Tsai, M. Brasse, R. G. Bergman and J. A. Ellman, Org. Lett.,
2011, 13, 540.
To our delight, heteroaromatic carboxamides 1r and 1s were
successfully allylated to furnish the corresponding products with a
good regioselectivity. In particular, C2-allylation of indole derivatives
is significant as it is crucial for the total synthesis of various natural
products.26 Finally, a,b-unsaturated carboxamides 1t and 1u also
participated in the oxidative allylation reaction to afford 3t and 3u in
moderate yields under current reaction conditions.
Next, we investigated the regioselectivity of rhodium and ruthe-
nium catalysts using 6a containing both the acetamido and pyrrol-
idinyl amide directing groups, as shown in Scheme 1. Under the
Rh-catalyzed oxidative allylation conditions reported by us27 and
Saa,28 no regioselectivity was observed between two ortho-C–H bonds
´
to afford indole 7a.29 Interestingly, the regioselective allylation using
Ru catalysis under standard reaction conditions was observed to give
7b in 33% yield with a 10 : 1 regioisomeric ratio.
To obtain the mechanistic insight, we carried out two parallel
reactions of 1f and deuterio-1f with allyl methyl carbonate (2a)
under standard reaction conditions, which resulted in the kinetic
isotope effect (kH/kD) of 1.28 (Scheme 2), thus indicating that C–H
bond cleavage is not involved in the rate-determining step.30
In conclusion, we disclosed ruthenium(II)-catalyzed oxidative
¨
allylation, crotylation and prenylation of (hetero)aromatic and 16 H. Wang, N. Schroder and F. Glorius, Angew. Chem., Int. Ed., 2013,
52, 5386.
a,b-unsaturated carboxamides with allylic carbonates. These
transformations have been applied to a wide range of substrates,
17 C. Feng, D. Feng and T.-P. Loh, Org. Lett., 2013, 15, 3670.
18 (a) G. Onodera, H. Imajima, M. Yamanashi, Y. Nishibayashi, M. Hidai
and typically proceed with complete linear g-selectivity of
substituted allylic carbonates.
This research was supported by the Basic Science Research
Program through the National Research Foundation of Korea
(NRF) funded by the Ministry of Education, Science and Tech-
nology (No. 2013R1A2A2A01005249).
and S. Uemura, Organometallics, 2004, 23, 5841; (b) A. B. Zaitsev,
¨
S. Gruber, P. A. Plu¨ss, P. S. Pregosin, L. F. Veiros and M. Worle, J. Am.
Chem. Soc., 2008, 130, 11604; (c) B. Sundararaju, M. Achard,
B. Demerseman, L. Toupet, G. V. M. Sharma and C. Bruneau, Angew.
Chem., Int. Ed., 2010, 49, 2782.
´
19 I. Fernandez, R. Hermatschweiler, F. Breher, P. S. Pregosin,
L. F. Veiros and M. J. Calhorda, Angew. Chem., Int. Ed., 2006, 45, 6386.
20 (a) T. Yao, K. Hirano, T. Satoh and M. Miura, Angew. Chem., Int. Ed.,
2011, 50, 2990; (b) Y. Makida, H. Ohmiya and M. Sawamura, Angew.
Chem., Int. Ed., 2012, 51, 4122; (c) S. Fan, F. Chen and X. Zhang,
Angew. Chem., Int. Ed., 2011, 50, 5918; (d) Y. B. Yu, S. Fan and
X. Zhang, Chem. – Eur. J., 2012, 18, 14643.
Notes and references
21 Y. J. Zhang, E. Skucas and M. J. Krische, Org. Lett., 2009, 11, 4248.
22 R. Zeng, C. Fu and S. Ma, J. Am. Chem. Soc., 2012, 134, 9597.
23 B. Ye and N. Cramer, J. Am. Chem. Soc., 2013, 135, 636.
1 For selected reviews of C–H bond functionalization, see:
(a) L. Ackermann, Chem. Rev., 2011, 111, 1315; (b) J. Wencel-
¨
Delord, T. Droge, F. Kiu and F. Glorius, Chem. Soc. Rev., 2011,
24 (a) S. Sharma, J. Park, E. Park, A. Kim, M. Kim, J. H. Kwak, Y. H. Jung
and I. S. Kim, Adv. Synth. Catal., 2013, 355, 332; (b) M. Kim, J. Park,
S. Sharma, A. Kim, E. Park, J. H. Kwak, Y. H. Jung and I. S. Kim,
Chem. Commun., 2013, 49, 925; (c) J. Park, M. Kim, S. Sharma,
E. Park, A. Kim, S. H. Lee, J. H. Kwak, Y. H. Jung and I. S. Kim, Chem.
Commun., 2013, 49, 1654; (d) S. Sharma, A. Kim, E. Park, J. Park,
40, 4740; (c) O. Baudoin, Chem. Soc. Rev., 2011, 40, 4902; (d) N. Kuhl,
M. N. Hopkinson, J. Wencel-Delord and F. Glorius, Angew. Chem.,
Int. Ed., 2012, 51, 10236; (e) J. J. Mousseau and A. B. Charette, Acc.
Chem. Res., 2013, 46, 412.
2 S. Murai, F. Kakiuchi, S. Sekine, Y. Tanaka, A. Kamatani, M. Sonoda
and N. Chatani, Nature, 1993, 366, 529.
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Chem. Commun., 2014, 50, 11303--11306 | 11305