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Volumn 46, Issue 25, 2007, Pages 4726-4728

Substrate-controlled asymmetric total synthesis of (+)-microcladallene B with a bromination strategy based on a nucleophile-assisting leaving group

Author keywords

Bromination; Dianion alkylation; Natural products; Nucleophile assisting leaving groups; Total synthesis

Indexed keywords

BROMINATION; CHEMOSELECTIVE SYNTHESIS; DIANION ALKYLATION; NATURAL PRODUCTS; NUCLEOPHILE ASSISTING LEAVING GROUPS; TOTAL SYNTHESIS;

EID: 34347223272     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200700854     Document Type: Article
Times cited : (39)

References (41)
  • 2
    • 0034647232 scopus 로고    scopus 로고
    • For total syntheses of α,α′-trans-oxocene natural products, see: a M. T. Crimmins, E. A. Tabet, J. Am. Chem. Soc. 2000, 122, 5473-5476;
    • For total syntheses of α,α′-trans-oxocene natural products, see: a) M. T. Crimmins, E. A. Tabet, J. Am. Chem. Soc. 2000, 122, 5473-5476;
  • 10
    • 33751003265 scopus 로고    scopus 로고
    • Angew. Chem. Int. Ed. 2006, 45, 7199-7202.
    • (2006) Chem. Int. Ed , vol.45 , pp. 7199-7202
    • Angew1
  • 16
    • 34347241939 scopus 로고    scopus 로고
    • in the case of 5′a, the enantiomer of the compound actually prepared is shown for comparison purposes.
    • b) in the case of 5′a, the enantiomer of the compound actually prepared is shown for comparison purposes.
  • 21
    • 34347251426 scopus 로고    scopus 로고
    • for the synthesis of α,α′-trans-oxocene natural products by RCM, see ref. [2a,b].
    • c) for the synthesis of α,α′-trans-oxocene natural products by RCM, see ref. [2a,b].
  • 24
    • 34347225413 scopus 로고    scopus 로고
    • To the best of our knowledge, this pyranoannulation constitutes the first example of the use of the protocol of Nakata and coworkers for the synthesis of a cis-fused bicyclic structure.
    • To the best of our knowledge, this pyranoannulation constitutes the first example of the use of the protocol of Nakata and coworkers for the synthesis of a cis-fused bicyclic structure.
  • 26
    • 34347247894 scopus 로고    scopus 로고
    • the free hydroxy group at C12 in 2 was found to be necessary for the efficient chemoselective reduction of the ester functionality in the presence of the α-alkoxy amide group, possibly by internal delivery of the hydride.
    • b) the free hydroxy group at C12 in 2 was found to be necessary for the efficient chemoselective reduction of the ester functionality in the presence of the α-alkoxy amide group, possibly by internal delivery of the hydride.
  • 27
    • 0000519465 scopus 로고    scopus 로고
    • 4NBr in xylene at reflux according to the double-inversion protocol of Masamune and co-workers produced the corresponding bromide in only moderate (20 %) yield as a 2:1 mixture of α and β isomers, along with a significant amount of elimination products: a) A. Fukuzawa, H. Sato, T. Masamune, Tetrahedron Lett. 1987, 28, 4303-4306;
    • 4NBr in xylene at reflux according to the double-inversion protocol of Masamune and co-workers produced the corresponding bromide in only moderate (20 %) yield as a 2:1 mixture of α and β isomers, along with a significant amount of elimination products: a) A. Fukuzawa, H. Sato, T. Masamune, Tetrahedron Lett. 1987, 28, 4303-4306;
  • 36
    • 34347211254 scopus 로고    scopus 로고
    • to the best of our knowledge, this reaction is the first example of trisylation under Mitsunobu conditions
    • c) to the best of our knowledge, this reaction is the first example of trisylation under Mitsunobu conditions.
  • 40
    • 34347258002 scopus 로고    scopus 로고
    • We were unable to obtain the spectra of the natural product from Dr. D. J. Kennedy as a result of his retirement
    • We were unable to obtain the spectra of the natural product from Dr. D. J. Kennedy as a result of his retirement.
  • 41
    • 34347249776 scopus 로고    scopus 로고
    • Characterization of synthetic 1: Rf, 0.21 (hexane/ethyl acetate, 10:1, m.p. 84-88°C; 1H NMR (500 MHz, CDCl3, δ, 6.11 (1 H, dd, J, 5.9, 2.8 Hz, 1 H, 5.85-6.00 (m, 2 H, 5.81 (ddd, J, 17.2, 10.3,10.3 Hz, 1 H, 5.41-5.45 (m, 2 H, 5.32 (d, J, 10.5 Hz, 1 H, 4.83 (ddd, J, 7.2, 3.5, 3.5 Hz, 1 H, 4.08 (ddd, J, 12.4, 10.1, 4.3 Hz, 1 H, 3.89 (dd, J, 10.2, 6.8 Hz, 1 H, 3.83 (bs, 1 H, 3.69 (dd, J, 9.8, 4.6 Hz, 1 H, 2.65-2.67 (m, 1 H, 2.60 (ddd, J, 12.8, 9.8, 3.0 Hz, 1 H, 2.52 (ddd, J, 7.8, 3.8, 3.8 Hz, 1 H, 2.27-2.33 (m, 2 H, 2.17 ppm (ddd, J, 12.7, 11.5, 3.2 Hz, 1 H, 13C NMR 125 MHz, CDCl3, δ, 202.6, 135.4, 129.3, 128.7, 119.4, 100.0, 83.3, 80.6, 74.9, 74.4, 69.9, 48.0, 43.2, 31.7, 30.2 ppm
    • 3): δ = 202.6, 135.4, 129.3, 128.7, 119.4, 100.0, 83.3, 80.6, 74.9, 74.4, 69.9, 48.0, 43.2, 31.7, 30.2 ppm.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.