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Volumn 10, Issue 21, 2008, Pages 4843-4846

Synthesis of amphidinolide e C10-C26 fragment

Author keywords

[No Author keywords available]

Indexed keywords

ALKALI; AMPHIDINOLIDE E; CARBON; CROSS LINKING REAGENT; FUSED HETEROCYCLIC RINGS; UNCLASSIFIED DRUG;

EID: 58149157811     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol801923y     Document Type: Article
Times cited : (18)

References (61)
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    • Very recent reviews: (a) Kobayashi, J.; Kubota, T. J. Nat. Prod. 2007, 70, 451.
    • Very recent reviews: (a) Kobayashi, J.; Kubota, T. J. Nat. Prod. 2007, 70, 451.
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    • Ph.D. Thesis in process
    • (f) Esteban, J. Ph.D. Thesis in process (2005-2008).
    • (2005)
    • Esteban, J.1
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    • Total syntheses: (a) Kim, C. H.; An, H. J.; Shin, W. K.; Yu, W.; Woo, S. K.; Jung, S. K.; Lee, E. Angew. Chem., Int. Ed. 2006, 45, 8019.
    • Total syntheses: (a) Kim, C. H.; An, H. J.; Shin, W. K.; Yu, W.; Woo, S. K.; Jung, S. K.; Lee, E. Angew. Chem., Int. Ed. 2006, 45, 8019.
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    • For diastereomers of amphidinolide E, see: c
    • For diastereomers of amphidinolide E, see: (c) Va, P.; Roush, W. R. Org. Lett. 2007, 9, 307.
    • (2007) Org. Lett , vol.9 , pp. 307
    • Va, P.1    Roush, W.R.2
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    • C6-C21, For syntheses of segments, see: a
    • For syntheses of segments, see: (a) Marshall, J. A.; Schaaf, G.; Nolting, A. Org. Lett. 2005, 7, 5331 (C6-C21).
    • (2005) Org. Lett , vol.7 , pp. 5331
    • Marshall, J.A.1    Schaaf, G.2    Nolting, A.3
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    • Two approaches were envisaged by us at the very beginning of this project (ref 2f) for the key steps: (i) a macrolactonization under the mildest possible conditions (to avoid epimerization at C2) as the last step, after a J-K reaction (C9-C10 bond); (ii) a ring-closing metathesis under appropriate conditions in the final step, after the ester formation.
    • Two approaches were envisaged by us at the very beginning of this project (ref 2f) for the key steps: (i) a macrolactonization under the mildest possible conditions (to avoid epimerization at C2) as the last step, after a J-K reaction (C9-C10 bond); (ii) a ring-closing metathesis under appropriate conditions in the final step, after the ester formation.
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    • Also see ref 2b
    • (d) Also see ref 2b.
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    • We prepared 3 from the Li enolate of N-propanoyl-4(S)-benzyloxazolidin-2-one and 2,3-dibromopropene. Its enantiomer is known: (a) Evans, D. A.; Kim, A. S. J. Am. Chem. Soc. 1996, 118, 11323.
    • We prepared 3 from the Li enolate of N-propanoyl-4(S)-benzyloxazolidin-2-one and 2,3-dibromopropene. Its enantiomer is known: (a) Evans, D. A.; Kim, A. S. J. Am. Chem. Soc. 1996, 118, 11323.
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    • According to the Kishi rule (Cha, J. K.; Christ, W. J.; Kishi, Y. Tetrahedron 1984, 40, 2247), they should be 11a and 11b, respectively.
    • According to the Kishi rule (Cha, J. K.; Christ, W. J.; Kishi, Y. Tetrahedron 1984, 40, 2247), they should be 11a and 11b, respectively.
  • 45
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    • See Supporting Information for the corresponding spectra. The largest HCCH coupling constant in the key moiety of 11b indicates an almost antiperiplanar arrangement of HIS and HIC, whereas the very small gauche 3J(H17H18) suggests a dihedral angle closer to 90° than to 60° (see the Newman projection through the C18-C17 bond in Figure 1, left, The value of 3J(H17COH) is also worth noting. The most relevant NOEs agree with these observations (with H16, H17, H18, Me29, and H 20 in the same, rear face, The depicted hydrogen bondings likely help to fix the conformation shown in Figure 1 left
    • 20 in the same, rear face). The depicted hydrogen bondings likely help to fix the conformation shown in Figure 1 (left).
  • 46
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    • 29 may be accounted for by the main conformation depicted in Figure 1 (right); other possible minor rotamers (by counterclockwise 60° rotation of the C19-C18 bond and/or by clockwise rotation of the C18-C17 bond) cannot be ruled out.
    • 29 may be accounted for by the main conformation depicted in Figure 1 (right); other possible minor rotamers (by counterclockwise 60° rotation of the C19-C18 bond and/or by clockwise rotation of the C18-C17 bond) cannot be ruled out.
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    • HSQC, and HMBC)
    • The structure of 13 was assigned on the basis of 2D-NMR spectra COSY
    • HH) are relevant,
    • HH) are relevant
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    • The oxygen atom of the oxolane ring may play a role in this selective cleavage. We would have preferred the reverse cleavage, to obtain mainly the C17-OPMB isomer, saving two steps, since later we need C 18-OH free (and, in principle, C 17-OH protected).
    • (b) The oxygen atom of the oxolane ring may play a role in this selective cleavage. We would have preferred the reverse cleavage, to obtain mainly the C17-OPMB isomer, saving two steps, since later we need C 18-OH free (and, in principle, C 17-OH protected).
  • 49
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    • Several CM of this etheneboronate ester (2-ethenyl-4,4,5,5-tetramethyl-1, 3,2-dioxaborolane), with the Grubbs II reagent, have been reported: (a) Morrill, C.; Grubbs, R. H. J. Org. Chem. 2003, 68, 6031 (and refs 13 and 14 therein).
    • Several CM of this etheneboronate ester (2-ethenyl-4,4,5,5-tetramethyl-1, 3,2-dioxaborolane), with the Grubbs II reagent, have been reported: (a) Morrill, C.; Grubbs, R. H. J. Org. Chem. 2003, 68, 6031 (and refs 13 and 14 therein).
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    • Very recent review of potassium organotrifluoroborates: Darses, S.; Genet, J.-P. Chem. Rev. 2008, 108, 288.
    • Very recent review of potassium organotrifluoroborates: Darses, S.; Genet, J.-P. Chem. Rev. 2008, 108, 288.
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    • 3. See: (a) Molander, G. A.; Felix, L. A. J. Org. Chem. 2005, 70, 3950.
    • 3. See: (a) Molander, G. A.; Felix, L. A. J. Org. Chem. 2005, 70, 3950.
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    • 2O (300 mol %) in DMF. Compare: (a) Gopalarathnarn, A.; Nelson, S. G. Org. Lett. 2006, 8, 7.
    • 2O (300 mol %) in DMF. Compare: (a) Gopalarathnarn, A.; Nelson, S. G. Org. Lett. 2006, 8, 7.
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    • Most recent review: Doucet, H. Eur. J. Org. Chem. 2008, 2013.
    • (c) Most recent review: Doucet, H. Eur. J. Org. Chem. 2008, 2013.
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    • Oxidative removal (e.g., with DDQ) of PMP and PMB groups is counterindicated as conjugate dienes are too sensitive; for an overview, see: Wutts, P. G. M.; Greene, T. W. Protective Groups in Organic Synthesis, 4th ed.; Wiley: Hoboken, 2007, p 124.
    • Oxidative removal (e.g., with DDQ) of PMP and PMB groups is counterindicated as conjugate dienes are too sensitive; for an overview, see: Wutts, P. G. M.; Greene, T. W. Protective Groups in Organic Synthesis, 4th ed.; Wiley: Hoboken, 2007, p 124.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.