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Volumn 38, Issue 7, 1999, Pages 923-925

Total synthesis of the proposed structure of (+)-tolyporphin A O,O-diacetate

Author keywords

Glycosides; Natural products; Porphyrinoids; Total synthesis

Indexed keywords

ACETOACETIC ACID; PORPHYRIN DERIVATIVE;

EID: 0033119791     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1521-3773(19990401)38:7<923::AID-ANIE923>3.0.CO;2-7     Document Type: Article
Times cited : (49)

References (37)
  • 6
    • 0001215610 scopus 로고
    • For seminal work by Eschenmoser and co-workers in this area, see the following reviews: a) A. Eschenmoser, Q. Rev. Chem. Soc. 1970, 24, 366;
    • (1970) Q. Rev. Chem. Soc. , vol.24 , pp. 366
    • Eschenmoser, A.1
  • 16
    • 85034513524 scopus 로고    scopus 로고
    • note
    • For the stereochemical assignment of the quaternary centers, see reference [18].
  • 17
    • 33745149667 scopus 로고    scopus 로고
    • Ph.D. Thesis, Harvard University
    • Satisfactory spectroscopic data were obtained for all new compounds reported: T. G. Minehan, Ph.D. Thesis, Harvard University, 1998.
    • (1998)
    • Minehan, T.G.1
  • 18
    • 85034510593 scopus 로고    scopus 로고
    • note
    • Glycosidation of substrates having less reactive acyl carbonyl groups such as the bis-O-benzoate and the bis-O-para-methoxybenzoate corresponding to 5 was also tested, but the major product in each case was still found to arise from C-C bond formation at the carbonyl carbon atom of the acyl group at C2.
  • 19
    • 85034506976 scopus 로고    scopus 로고
    • note
    • Base hydrolysis followed by acid work-up yielded three lactones. Treatment with methyllithium or diisobutyl aluminum hydride (DIBAL-H) yielded a ketal or acetal involving the alcohol groups of C9 and C2; attempted hydrolysis of the resultant acetal or ketal failed under a wide range of acidic conditions. Efforts to incorporate "removable" α-quaternary ester protecting groups, for example the α,α-dimethyllevulinoyl group, also met with limited success.
  • 20
    • 85034505713 scopus 로고    scopus 로고
    • note
    • The product at this stage was a mixture of diastereomers due to the chiral centers at C3, C6, C12, and/or C16.
  • 21
    • 85034519406 scopus 로고    scopus 로고
    • note
    • Because of its extreme sensitivity to light, purification and manipulation of the cadmium precorphin complex corresponding to 15 presented technical difficulties, resulting in poor overall yields; thus, the nickel-containing substrate was used for further elaboration.
  • 22
    • 85034508911 scopus 로고    scopus 로고
    • note
    • [4] that this cyclization involves three distinct steps: 1) a slow reaction of the lactam carbonyl with the alkylating reagent, 2) a proton-catalyzed isomerization of the double bonds in the precorphin structure, and 3) an elcctrocyclic ring closure. The addition of methanol serves to release a controlled amount of "catalytic protons" into the reaction medium.
  • 23
    • 85034508155 scopus 로고    scopus 로고
    • note
    • [3]
  • 25
    • 85034514098 scopus 로고    scopus 로고
    • note
    • [3]
  • 36
    • 85034510591 scopus 로고    scopus 로고
    • note
    • [2a]
  • 37
    • 85034511240 scopus 로고    scopus 로고
    • note
    • 1H NMR spectra, the synthetic material was once again found not to match the authentic sample.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.