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9
To understand the selectivity of the insertion, the
M. M. Díaz-Requejo, M. Costas and P. DJ.OPIé: 1r0e.z1,03A9n/gCe7CwC.0C0h7e1m8C.
Int. Ed., 2016, 55, 6530; (b) Y. Cai, S.-F. Zhu, G.-P. Wang and
Q.-L. Zhou, Adv. Synth. Catal., 2011, 353, 2939.
(a) D. F. Taber, J. C. Amedio Jr., R. G. Sherill, J. Org. Chem.
1986, 51, 3382; (b) M. L. Rosenberg, J. H. F. Aasheim, M.
Trebbin, E. Uggerud and T. Hansen, Tetrahedron Lett., 2009,
50, 6506.
formation of the possible
shown in Figure 1, the corresponding pathway leading to
lactam 2b is rather similar to that computed for oxindole 3b
β-lactam 2b was also computed. As
β
-
,
i.e. Pd-mediated 1,4-H migration via TS1-B followed by
reductive elimination through TS2-B. From the data in Figure
1, it becomes evident that both reaction steps are associated
with much higher activation barriers than those computed for
the pathway involving TS1-A and TS1-B. In particular, the
rather high barrier computed for the reductive elimination via
TS2-B (∆G≠ = 42.8 kcal/mol) makes this step unfeasible.
Therefore, it can be concluded that the complete selectivity of
10 For the insertion in terminal alkynes, see: J. M. Goll and E.
Fillion, Organometallics, 2008, 27, 3622.
11 D. Solé, F. Mariani, M.-L. Bennasar and I. Fernández, Angew.
Chem. Int. Ed., 2016, 55, 6467.
12 (a) P. M. P. Gois and C. A. M. Afonso, Eur. J. Org. Chem. 2004,
3773; (b) A. Ring, A. Ford and A. R. Maguire, Tetrahedron
Lett., 2016, 57, 5399.
13 (a) H. M. L. Davies and R. E. J. Beckwith, Chem. Rev., 2003,
103, 2861; (b) C. A. Merlic and A. L. Zechman, Synthesis,
2003, 1137; (c) H. M. L. Davies and D. Morton, Chem. Soc.
Rev., 2011, 40, 1857; (d) C. Zheng and S.-L. You, RSC Adv.,
the process, which exclusively produces oxindoles over
lactams, takes place mainly under kinetic control.
β-
In summary, we have shown that palladium catalysis
constitutes an useful alternative to promote the carbenoid C–
2014, 4, 6173; (e) A. DeAngelis, R. Panish and J. M. Fox, Acc.
Chem. Res., 2016, 49, 115.
14 For selected examples, see: (a) M. P. Doyle, M. S. Shanklin, H.
Q. Pho and S. N. Mahapatro, J. Org. Chem., 1988, 53, 1017;
H insertion of α-diazo-α-(methoxycarbonyl)acetanilides, which
selectively occurs into the arylic C(sp2)–H bond rather than the
C(sp3)–H bonds. Moreover, when using DCE as the solvent, the
insertion is followed by alkylation to give 3-
(chloroethyl)oxindoles. Although the carbenoid insertion into
(b) A. G. H. Wee, B. Liu and L. Zhang, J. Org. Chem., 1992, 57
4404; (c) D. S. Brown, M. C. Elliott, C. J. Moody, T. J.
Mowlem, J. P. Marino and A. Padwa, J. Org. Chem., 1994, 59
,
,
the
arylic
C–H bond
starting
from
α-diazo-α-
2447; (d) S. Miah, A. M. Z. Slawin, C. J. Moody, S. M.
Sheedan, J. P. Marino, M. A. Semones, A. Padwa and I. C.
Richards, Tetrahedron, 1996, 52, 2489; (e) H. Qiu, M. Li, L.-Q.
Jiang, F.-P. Lv, l. Zan, C.-W. Zhai, M. P. Doyle and W.-H. Hu,
(alkoxycarbonyl)acetanilides can also be promoted by
rhodium(II) perfluorocarboxamides,14c-d these catalysts are not
commercially produced. Thus, considering the ready
availability of Pd2(dba)3 in particular, the present process
would complement the existing methodologies based on the
use of Rh as well as Ru catalysts.
Nat. Chem., 2012, 4, 733.
15 (a) W.-W. Chan, T.-L. Kwong and W.-Y. Yu, Org. Biomol.
Chem., 2012, 10, 3749; (b) N. Liu, Q.-P. Tian, Q. Yang and S.-
D. Yang, Synlett, 2016, 2621; (c) K. Yamamoto, Z. Qureshi, J.
Tsoung, G. Pisella and M. Lautens, Org. Lett., 2016, 18, 4954.
16 Y. Deng, C. Jing, H. Arman and M. P. Doyle, Organometallics,
2016, 35, 3413.
We gratefully acknowledge financial support for this work
from MINECO-FEDER (Projects CTQ2013-44303-P, CTQ2014-
51912-REDC, CTQ2015-64937-R and CTQ2016-78205-P).
17 S. Ghosh, S. Chaudhuri and A. Bisai, Org. Lett., 2015, 17
1373.
,
18 For related metal-free carbene-insertion reactions, see: M.
Kischkewitz, C.-G. Daniliuc and A. Studer, Org. Lett., 2016,
18, 1206. See also reference 14a.
Notes and references
1
For recent reviews, see: (a) A. Ford, H. Miel, A. Ring, C. N.
Slattery, A. R. Maguire and M. A. McKervey, Chem. Rev.,
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19 For recent examples on the synthesis of oxindoles, see: (a)
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20 Treatment of 1a with Pd2(dba)3 (0.1), Cs2CO3 (2) and
phenylvinylsulfone (1.1) in toluene at reflux afforded 3a
(60%). No traces of the corresponding Michael addition
product were observed in the reaction crude.
2
(a) M. P. Doyle, R. Duffy, M. Ratnikov and L. Zhou, Chem.
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22 Treatment of 1a with Pd(PPh3)4 (0.2) without any base in DCE
at reflux afforded a complex mixture, in which 3a and N-
benzyl-2-oxindole were identified as the main products.
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(a) M. K-W. Choi, W.-Y. Yu and C.-M. Che, Org. Lett. 2005,
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24 The identity of β-lactam 2b was fully confirmed by
comparison with an authentic sample prepared by treatment
of 1b with Rh2(OAc)4, see the ESI.
7
(a) X.-G. Liu, S.-S. Zhang, J.-Q. Wu, Q. Li and H. Wang,
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All calculations were carried out at the PCM(dichloroethane)-
M06L/def2-TZVPP // PCM(dichloroethane)-B3LYP-D3/def2-
SVP level. See computational details in the ESI.
4 | J. Name., 2012, 00, 1-3
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