- Total synthesis of the postulated structure of fulicineroside
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A total synthesis of the proposed structures of fulicineroside and its aglycone fulicinerine is reported. The tetrasubstituted dibenzofuran substructure was accessible either through a Pd-mediated ortho-metalation or by an Ir-catalyzed meta-borylation. The synthesis of the β,β,α- linked trisaccharide consisting of D-olivose, L-rhodinose, and L-rhamnose was challenged by the unprecedented β-linked rhodinose. A Pd-catalyzed β-selective glycosylation of a 4-epi-rhodinose and a subsequent Mitsunobu inversion provided selectively the β-linked L-rhodinose-L-rhamnose disaccharide. Comparison with the reported data for the natural product and the aglycone suggests a misassignment of the structure of the natural product. Natural product reassignment: Total synthesis of the proposed structures for fulicineroside and its aglycone fulicinerine has been achieved (see figure). Key issues were the tetrasubstituted dibenzofuran and the trisaccharide with its β-linkage between L-rhodinose and L-rhamnose. A comparison with the reported data for the natural product and the aglycone suggests a misassignment of the structure of the natural product. Copyright
- Bartholom?us, Ruben,Dommershausen, Fabian,Thiele, Markus,Karanjule, Narayan S.,Harms, Klaus,Koert, Ulrich
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supporting information
p. 7423 - 7436
(2013/06/27)
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- A short and efficient transformation of rhamnose into activated daunosamine, acosamine, ristosamine and epi-daunosamine derivatives, and synthesis of an anthracycline antibiotic acosaminyl-ε-iso-rhodomycinone
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3-Amino-2,3,6-trideoxyhexopyranoses are essential constituents of most anthracycline antitumour antibiotics. For an investigation of structure-activity relationships, the four diastereomeric amino sugars daunosamine, acosamine, ristosamine, and epidaunosamine were synthesised in short and efficient routes starting from commercially available rhamnose. Several glycosyl donors were provided and their use was exemplified in the synthesis of acosaminyl-ε-iso-rhodomycinone.
- Renneberg, Bernd,Li, Yue-Ming,Laatsch, Hartmut,Fiebig, Heinz-Herbert
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p. 861 - 872
(2007/10/03)
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- SYNTHESIS OF (L)-DAUNOSAMINE AND RELATED AMINO SUGARS
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1-(2-Furyl)ethanol (6) has been converted into methyl (+/-)-daunosaminide (1) and methyl (+/-)-ristosaminide (3) by use of an intramolecular cyclisation of a trichloroacetimidate group. (+/-)-Daunosamine (1) has been obtained more directly from the alcohol (10) by use of a modified Mitsunobu reaction; the scope of the latter reaction has been explored using cyclohex-2-en-1-ol as a model substrate.Asymmetric reduction of 2-acetylfuran (5) has given (S)-1-(2-furyl)ethanol (46) in good enantiomeric excess, thus providing a short route to the L-enantiomers of the amino sugars (1), (2), and (3) from a cheap, non-carbohydrate precursor.
- Sammes, Peter G.,Thetford, Dean
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p. 111 - 124
(2007/10/02)
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- Syntheses of Biologically Important Carbohydrates, 33. - Syntheses of Unsaturated Amino Sugars and Aminoalkyl-branched Carbohydrates via Sigmatropic Rearrangement of Trichloroacetimidates
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Starting with the α-D-erythro-hex-3-enopyranoside 1 the isomers with β-D-erythro as well as α- and β-D-threo configuration 5b, 3b, and 9 are prepared.In Mitsunobu reactions the 1,2-cis derivatives 1 and 9 smoothly undergo SN2-type substitutions
- Dyong, Ingolf,Weigand, Joachim,Thiem, Joachim
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p. 577 - 599
(2007/10/02)
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- HEMISYNTHESE DE NOUVEAUX GLICOSIDES ANALOGUES DE LA DAUNORUBICINE
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Seven daunorubicin analogs containing α-L-, α-D-, and β-D-glicosidic linkages, in which the natural occuring sugar (L-daunosamine) was replaced by diastereomeric 3-amino-2,3,6-trideoxyhexoses (3-epi-L-daunosamine, D-acosamine, D-daunosamine, D-ristosamine, and 3-epi-D-daunosamine), were prepared.In all cases, glycosidation with daunomycinone was performed in the presence of p-toluenesulfonic acid starting from 1-O-acetyl-2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoro-acetamidohexopyranoses (prepared from the corresponding methyl 3-amino-2,3,6-trideoxyhexopyranosides) or from 1,5-anhydro-2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoroacetamidohex-1-enitols (prepared from glycosals or pseudoglycals, the 3-amino group being introduced by substitution with sodium azide and subsequent reduction).Glycosidation was followed by removal of the protecting groups.
- Boivin, Jean,Montagnac, Alain,Monneret, Claude,Pais, Mary
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p. 223 - 242
(2007/10/02)
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