Please do not adjust margins
ChemComm
Page 4 of 4
DOI: 10.1039/C6CC10228J
COMMUNICATION
Journal Name
12. (a) C. J. Douglas and L. E. Overman, Proc. Natl. Acad. Sci. U.S.A.,
2004, 101, 5363. (b) C. V. Galliford and K. A. Scheidt, Angew. Chem., Int.
Ed., 2007, 46, 8748. (c) F. Zhou, Y. L. Liu and J. A. Zhou, Adv. Synth.
Catal., 2010, 352, 1381.
13. Synthesis of 3-acyl-2-oxindoles, see; (a) Y. X. Jia and E. P. Kundig,
Angew. Chem., Int. Ed., 2009, 48, 1636. (b) A. Perry and R. J. K. Taylor,
Chem. Commun., 2009, 3249. (c) S. Ghosh, S. De, B. N. Kakde, S. Bhunia,
A. Adhikary and A. Bisai, Org. Lett., 2012, 14, 5864.
the first total synthesis of meso-folicanthine (17d). The X-ray
analysis of 17d proved the formation of bis-pyrroloindoline
structure (Figure 3). On the other hand, reduction of meso-23b
afforded meso-24, from where the total synthesis of meso-
chimonanthine (17c) was accomplished by hydrogenolysis in
the presence of Pd-C under 1 atm. Since, the total synthesis of
meso-calycanthine (18a) is known from meso-chimonanthine
(
17c),23 our efforts culminated in formal total synthesis of
18a 26
14. An efficient deacylative oxidation of 3-acyl-2-oxindoles can be
performed under O2-atmosphere. For details, see ESI.
.
In summary, we have developed an effective protocol
involving Pd(0)-catalyzed deacylative allylation (DaA) of 2-
oxindoles sharing acyl functionality with readily available allylic
alcohols through retro-Claisen reaction. The process can also
be used in tandem fashion with the Tsuji–Trost allylation of
stabilized enolate generated from N-acyl-2-oxindole to enable
the controlled dialkylations at 3-position of 2-oxindoles
15. Enolacetate 9a alone afforded 6a in 89% isolated yield, indicating
enolate 4 (Scheme 1) equilibrate under the reaction condition.
16. For geranylated hexahydropyrrolo[2,3-b]indole based alkaloids, see;
(a) M. Okada, I. Sato, S. J. Cho, D. Dubnau and Y. Sakagami,
Tetrahedron, 2006, 62, 8907. (b) S. J. Rochfort, S. Moore, C. Craft, N. H.
Martin, R. M. V. Wagoner and J. L. C. Wright, J. Nat. Prod., 2009, 72,
1773. For related complex pyrroloindoline alkaloids, see; (c) L. Furst, J.
through a three-component coupling. Control experiments M. R. Narayanam and C. R. J. Stephenson, Angew. Chem., Int. Ed., 2011,
50, 9655. (d) Y. Sun, R. Li, W. Zhang and A. Li, Angew. Chem., Int. Ed.,
2013, 52, 9201.
17. For Pd-catalyzed asymmetric prenylations and geranylations, see; B.
M. Trost, S. Malhotra and W. H. Chan, J. Am. Chem. Soc., 2011, 133,
7328.
entailed the intermolecular nature of decarboxylative
processes. The methodology is ultimately employed in the
concise total syntheses of meso-folicanthine (17d) and meso-
chimonanthine (17c).
18. T. Maji, K. Ramkumar and J. A. Tunge, Chem. Commun., 2014, 50,
14045.
Financial supports from the DST [SR/S1/OC-54/2011] and CSIR
[02(0013)/11/EMR-II], Govt. of India are gratefully acknowledged.
N. K. and M.K.D. thank the CSIR for SRFs. S.G. thanks IISER Bhopal
for Post-doctoral fellowship.
19. (a) R. Kuwano, Synthesis, 2009, 7, 1049. (b) R. Kuwano, Y. Konda and
Y. Matsuyama, J. Am. Chem. Soc., 2003, 125, 12104. (c) B. M. Trost and
L. C. Czabaniuk, J. Am. Chem. Soc., 2010, 132, 15534. (d) A. Recio, III, J.
D. Heinzman and J. A. Tunge, Chem. Commun., 2012, 48, 142. (e) B. M.
Trost and L. C. Czabaniuk, J. Am. Chem. Soc., 2012, 134, 5778.
Notes and references
1. (a) R. Martin and S. L. Buchwald, Acc. Chem. Res., 2008, 41, 1461. (b) 20. In general, electrophiles containing
a
naphthalene or
N. Marion and S. P. Nolan, Acc. Chem. Res., 2008, 41, 1440. (c) S. E. heteroaromatic moiety where the barrier to ionization and
Denmark and C. S. Regens, Acc. Chem. Res., 2008, 41, 1486. dearomatization is essentially lower, are good substrates for Pd(0)-
2. (a) I. Shimizu, T. Yamada and J. Tsuji, Tetrahedron Lett. 1980, 21, catalyzed benzylation reactions.
3199. (b) J. Tsuji, I. Minami and I. Shimizu, Tetrahedron Lett. 1983, 24, 21. (a) L. E. Overman, D. V. Paone and B. A. Sterns, J. Am. Chem. Soc.,
1793.
1999, 121, 7702. (b) M. Movassaghi and M. A. Schmidt, Angew. Chem.,
3. (a) B. M. Trost and M. L. Crawley, Chem. Rev., 2003, 103, 2921. (b) J. Int. Ed., 2007, 46, 3725.
D. Weaver, A. Recio III, A. J. Grenning and J. A. Tunge, Chem. Rev., 2011, 22. P. Ruis-Sanchis, S. A. Savina, F. Alberecio and M. Álvarez, Chem. -Eur.
111, 1846.
J., 2011, 17, 1388.
4. (a) J. T. Mohr, D. C. Behenna, A. W. Harned and B. M. Stoltz, Angew. 23. Acid catalyzed isomerization of 17c is reported to give meso-
Chem., Int. Ed., 2005, 44, 6924. (b) E. C. Burger and J. A. Tunge, J. Am. calycanthine (18a), see: (a) J. T. Link and L. E. Overman, J. Am. Chem.
Chem. Soc., 2006, 128, 10002. (c) A. Recio III and J. A. Tunge, Org. Lett., Soc., 1996, 118, 8166. (b) C. Menozzi, P. I. Dalko and J. Cossy, Chem.
2009, 11, 5630. (d) A. J. Grenning and J. A. Tunge, Org. Lett., 2010, 12, Commun., 2006, 4638.
740.
5. Y. Numajiri, G. Jiménez-Osés, B. Wang, K. N. Houk and B. M. Stoltz, bisalkylations, see; S. B. Hoyt and L. E. Overman, Org. Lett., 2000, 2,
Org. Lett., 2015, 17, 1082 and reference cited. 3241.
24. For synthesis of dimeric 2-oxindoles from dihydroisoindigo via
6. (a) J. A. Enquist Jr. and B. M. Stoltz, Nature, 2008, 453, 1228. (b) B. M. 25. Red-Al reduction of Boc-protected diamines meso-22a-b led to
Trost and M. Osipov, Angew. Chem., Int. Ed., 2013, 52, 9176. (c) S. multitude spots on TLC.
Ghosh, S. Bhunia, S. De, B. N. Kakde and A. Bisai, Chem. Commun., 2014,
50, 2434.
26. (a) (±)-20a is an advanced intermediate for total synthesis of
(±)-folicanthine (17b), see; (a) S. Ghosh, S. Chaudhuri and A. Bisai,
Chem. -Eur. J., 2015, 21, 17479. (b) S. Ghosh, S. Chaudhuri and A.
Bisai, Org. Lett., 2015, 17, 1373.
7. Nitroalkane pKa’s: F. G. Bordwell, N. R. Vanier, W. S. Matthews, J. B.
Hendrickson, P. L. Skipper, J. Am. Chem. Soc., 1975, 97, 7160.
8. A. J. Grenning and J. A. Tunge, Angew. Chem., Int. Ed., 2011, 50, 1688.
9. References pertaining to C-C bond cleavage by retro-Claisen reaction,
see: (a) C. Han, E. H. Kim and D. A. Colby, J. Am. Chem. Soc., 2011, 133,
5802. (b) C. He, S. Guo, L. Huang and A. Lei, J. Am. Chem. Soc., 2010,
132, 8273 and references therein.
10. (a) Ketone pKa’s: F. G. Bordwell and J. A. Harrelson, Jr. Can. J. Chem.,
1990, 68, 1714. (b) Nitrile pKa’s: F. G. Bordwell, J.-P. Cheng, M. J. Bausch
and J. E. Bares, J. Phys. Org. Chem., 1988, 1, 209.
11. (a) A. J. Grenning and J. A. Tunge, J. Am. Chem. Soc., 2011, 133,
14785. (b) A. J. Grenning, C. K. V. Allen, T. Maji, S. B. Lang and J. A.
Tunge, J. Org. Chem., 2013, 78, 7281. (c) For a deacylative benzylation
(DaB), see; T. Maji, K. Ramkumar and J. A. Tunge, Chem. Commun.,
2014, 50, 14045.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins