Total synthesis of angucyclines. 9. An Alternative Biomimetic-Type Synthesis of 8-Deoxytetrangomycin
摘要:
Base-catalyzed cyclization of the naphthoquinone 5 afforded the 1,2-dihydroanthraquinone 6a. The bisallcylation products 9 and 10 were obtained by Stille-type chain elongation of the corresponding triflate 6b with the stannanes 7 or 8. The dihydroanthraquinone 9 is a potential precursor for the SS-228 Y-type angucyclinones, where as the diketone 10 can be converted to 8-deoxytetrangomycin (11).
Total synthesis of angucyclines. 9. An Alternative Biomimetic-Type Synthesis of 8-Deoxytetrangomycin
作者:Karsten Krohn、Nasir Hayat
DOI:10.1002/prac.19983400211
日期:——
Base-catalyzed cyclization of the naphthoquinone 5 afforded the 1,2-dihydroanthraquinone 6a. The bisallcylation products 9 and 10 were obtained by Stille-type chain elongation of the corresponding triflate 6b with the stannanes 7 or 8. The dihydroanthraquinone 9 is a potential precursor for the SS-228 Y-type angucyclinones, where as the diketone 10 can be converted to 8-deoxytetrangomycin (11).
Synthesis of Angucyclines. 8. Biomimetic-Type Synthesis of Rabelomycin, Tetrangomycin, and Related Ring B Aromatic Angucyclinones
The angucyclinones with aromatic ring B (1a-c and 2a-c) are prepared in a biomimetic-typesynthesis by two successive aldol cyclizations starting from the substituted naphthoquinones 12a-c. In both cyclization steps the C-H acidity of the potential nucleophilic centers determines the mode of cyclization under kinetically controlled conditions. The tetrahydroanthraquinones 13a-c/14a-c are hydroxylated