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Article
(10) Yamano, Y.; Arai, M.; Kobayashi, M. Bioorg. Med. Chem. Lett.
2012, 22, 4877−4881.
out the reduction in solution after the cyclization step. Several
conditions were tested, such as Staudinger reaction, SnCl2 treatment,
hydrogenation with Pd, and Lindlar catalysts and Zn, but all of them
failed since the quality of the crude product decreased. Finally, the
Thr(NH2) residue was found to be the best choice to facilitate the
synthesis of this complex natural depsipeptide.
(33) Skehan, P.; Storeng, R.; Scudiero, D.; Monks, A.; McMahon, J.;
Vistica, D.; Warren, J. T.; Bokesch, H.; Kenney, S.; Boyd, M. R. J. Natl.
Cancer Inst. 1990, 82, 1107−1112.
(11) Ratnayake, A. S.; Bugni, T. S.; Feng, X.; Harper, M. K.; Skalicky,
J. J.; Mohammed, K. A.; Andjelic, C. D.; Barrows, L. R.; Ireland, C. M.
J. Nat. Prod. 2006, 69, 1582−1586.
(12) Plaza, A.; Bifulco, G.; Keffer, J. L.; Lloyd, J. R.; Baker, H. L.;
Bewley, C. A. J. Org. Chem. 2009, 74, 504−512.
(13) Plaza, A.; Gustchina, E.; Baker, H. L.; Kelly, M.; Bewley, C. A. J.
Nat. Prod. 2007, 70, 1753−1760.
(14) Lu, Z.; Wagoner, R. M. V.; Harper, M. K.; Baker, H. L.; Hooper,
J. N. A.; Bewley, C. A.; Ireland, C. M. J. Nat. Prod. 2011, 74, 185−193.
(15) Zampella, A.; Sepe, V.; Luciano, P.; Bellotta, F.; Monti, M. C.;
́ ̂
D’Auria, M. V.; Jepsen, T.; Petek, S.; Adeline, M.-T.; Laprevote, O.;
Aubertin, A.-M.; Debitus, C.; Poupat, C.; Ahond, A. J. Org. Chem.
2008, 73, 5319−5327.
(16) Zampella, A.; Sepe, V.; Bellotta, F.; Luciano, P.; D’Auria, M. V.;
Cresteil, T.; Debitus, C.; Petek, S.; Poupat, C.; Ahond, A. Org. Biomol.
Chem. 2009, 7, 4037−4044.
́
(17) (a) Coello, L.; Fernandez, R.; Reyes, J. F.; Francesch, A.;
Cuevas, C. Int. Pat. Appl. WO 2010/070078 A1, 2010. (b) Pelay-
Gimeno, M.; García-Martín, Y.; Martin, M. J.; Spengler, J.; Molina-
Guijarro, J. M.; Munt, S.; Francesch, A. M.; Cuevas, C.; Tulla-Puche,
J.; Albericio, F. Nat. Commun. 2013, 4, No. 2352, DOI: 10.1038/
ncomms3352.
(18) Marfey, P. Carlsberg Res. Commun. 1984, 49, 591−596.
(19) (a) Liang, B.; Carroll, P. J.; Joullie, M. M. Org. Lett. 2000, 2,
4157−4160. (b) Schmidt, U.; Mundinger, K.; Riedl, B.; Haas, G.; Lau,
R. Synthesis 1992, 1201−1202. (c) Wagner, R.; Tilley, J. W.; Lovey, K.
Synthesis 1990, 785−786. (d) Mori, K.; Iwasawa, H. Tetrahedron 1980,
36, 87−90.
(20) Zampella, A.; D’Orsi, R.; Sepe, V.; Casapullo, A.; Monti, M. C.;
D’Auria, M. V. Org. Lett. 2005, 7, 3585−3588.
(21) (a) Lipton and co-workers have published the synthesis of
callipeltin B, a natural product with a similar cycle but terminated in
pyro-diMeGln, which faciliates the synthetic process:
Krishnamoorthy, R.; Vazquez-Serrano, L. D.; Turk, J. A.; Kowalski,
J. A.; Benson, A. G.; Breaux, N. T.; Lipton, M. A. J. Am. Chem. Soc.
2006, 128, 15392−15393. (b) Ma and co-workers have accomplished
an elegant synthesis of papuamide B carried out in solution that
comprises 27 linear steps and an overall yield of 7%: Xie, W.; Ding, D.;
Zi, W.; Li, G.; Ma, D. Angew. Chem. 2008, 120, 2886−2890.
(22) Sequences containing an N-alkylamino acid and a D-amino acid
are very prone for DKP formation.
(23) In order to establish the synthetic strategy, the simplified Tyr
derivative was used.
(24) Esterification with Fmoc-N-MeAla-OH was more difficult due
to steric hindrance of the Fmoc group.
(25) This could constitute another example of “conformationally
restricted mobility protection”: Tulla-Puche, J.; Marcucci, E.; Fermin,
M.; Bayo-Puxan, N.; Albericio, F. Chem.Eur. J. 2008, 14, 4475−
́
4478.
(26) Rama Rao, A. V.; Chakraborty, T. K.; Laxma Reddy, K.;
Srinivasa Rao, A. Tetrahedron Lett. 1994, 35, 5043−5046.
(27) (a) Acevedo, C. M.; Kogut, E. F.; Lipton, M. A. Tetrahedron
2001, 57, 6353−6359. (b) C
2005, 70, 6218−6221.
(28) (a) Mattingly, P. G.; Miller, M. J.; Cooper, R. D. G.; Daughtery,
B. W. J. Org. Chem. 1983, 48, 3556−3559. (b) Guzman-Martínez, A.;
VanNieuwenhze, M. S. Synlett 2007, 1513−1516.
(29) Calimsiz, S.; Morales Ramos, A. I.; Lipton, M. A. J. Org. Chem.
̧alimsiz, S.; Lipton, M. A. J. Org. Chem.
́
̧
2006, 71, 6351−6356.
(30) Steven, C. M.; Watanabe, R. J. Am. Chem. Soc. 1950, 72, 725−
727.
(31) Myers, A. G.; Yang, B. H.; Chen, H.; McKinstry, L.; Kopecky, D.
J.; Gleason, J. L. J. Am. Chem. Soc. 1997, 119, 6496−6511.
(32) First, Fmoc-Thr(N3)-OH was used as building block 10 because
of its easier elaboration. The reduction on solid phase was successful
with SnCl2, thiophenol, and DIPEA, but the protection of the new
amine was not achieved in high yields. So the alternative was to carry
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dx.doi.org/10.1021/ja502744a | J. Am. Chem. Soc. XXXX, XXX, XXX−XXX