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Volumn 61, Issue 4, 2005, Pages 977-1003

Synthesis of tri- and tetracyclic diterpenes. Cyclisations promoted by SmI 2

Author keywords

Samarium iodide; Stereoselective cyclisation; Tri and tetracyclic diterpenes; Zamoranic acid

Indexed keywords

ACID; CARBONYL DERIVATIVE; DITERPENE; IODINE; SAMARIUM;

EID: 19944376119     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tet.2004.09.116     Document Type: Article
Times cited : (12)

References (147)
  • 55
    • 11044233649 scopus 로고
    • Methods for the Oxidation of Organic Compounds
    • Academic London
    • A.H. Haines Methods for the Oxidation of Organic Compounds Alkanes, Alkenes, Alkynes and Arenes 1985 Academic London p 73
    • (1985) Alkanes, Alkenes, Alkynes and Arenes
    • Haines, A.H.1
  • 95
    • 11044239413 scopus 로고    scopus 로고
    • X-ray for 15. CCDC 213752.
    • X-ray for 15. CCDC 213752.
  • 118
    • 11044238598 scopus 로고    scopus 로고
    • note
    • 2=0.2717 for a total of 195 parameters. Crystallographic data (excluding structure factors) for this compound has been deposited at the Cambridge Crystallographic Data Centre as supplementary material no. CCDC 244343.
  • 119
    • 11044228063 scopus 로고    scopus 로고
    • note
    • The two dimensional structure of 37 was built using the sketcher in Maestro v5.1.016, supplied by Schrodinger, Inc, Portland, OR, USA, coupled to Macromodel v. 8.1.031 from the same supplier. The structure of 37 was energy-minimised using TNCG optimisation with a maximum of 5000 iterations to default convergence, with the MMFF94S forcefield, and a conformational search was then set up using the Maestro automatic setup routine with default parameters and the MCMM/Lowmode mixed method, with 1000 trials and the same optimisation and potential settings as previously. A total of 84 unique conformations were found, of which the global minimum (absolute MMFF94s energy 380.94 kJ/mol, found 7 times) showed the all-chair conformation and the next minimum (0.88 kJ/mol higher in energy, found 7 times) showed the chair-boat-chair conformation. Analysis of the boat or chair conformations of rings B and C was performed by measurement of appropriate torsion angles, and graphing of these angles against the MMFF94s energy (relative to the minimum) observed for each conformer. Identical studies were carried out on structures derived from the minimum found for 37 by epimerisation at C8 only, at C8, C13 and C14, or at C14 only, using both the same in vacuo conditions as above and in separate runs with the CHCl3 GB/SA solvation model available in MacroModel. The dihedral angles between H8 and H14, and between H13 and H14, were measured in Maestro for all conformations within 50 kJ/mol of the global minimum for all four structures. With respect to this dihedral angle, the lowest-energy conformer, or in the case of 37 the two lowest-energy conformers (all chair and chair-boat-chair), were representative of all conformers with energy within 20 kJ/mol of the global minimum.
  • 120
    • 11044224607 scopus 로고    scopus 로고
    • note
    • 2=0.2819. Crystallographic data (excluding structure factors) for this structure has been deposited at the Cambridge Crystallographic Data Centre as supplementary material no. CCDC 244342.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.