Cosme G Francisco

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The fragmentation of anomeric alkoxyl radicals (ARF) and the subsequent intramolecular cyclization promoted by hypervalent iodine reagents provide an excellent method for the synthesis of tetrazolo-sugars. This new reaction offers additional advantages for the synthesis of these compounds, including the ready availability of the starting materials,(More)
The reaction of specifically protected anhydroalditols with (diacetoxyiodo)benzene or iodosylbenzene and iodine is a mild and selective procedure for the synthesis of chiral 6,8-dioxabicyclo[3.2.1]octane and 2,7-dioxabicyclo[2.2.1]heptane ring systems under neutral conditions. This reaction can be considered to be an intramolecular glycosidation that goes(More)
[reaction: see text] The alkoxy radical generated by reaction of 3,7-anhydro-2-deoxyoctitols with (diacetoxyiodo)benzene (DIB) and iodine abstracts regioselectively either the proton at C7 or that at C4 depending on the electronegativity of the substituent at C4. The correct election of this substituent can switch the reaction to give(More)
The reaction of phenyl and benzyl amidophosphates and alkyl and benzyl carbamate derivatives of aminoalditols with (diacetoxyiodo)benzene or iodosylbenzene and iodine is a mild and selective procedure for the synthesis of chiral 7-oxa-2-azabicyclo[2.2.1]heptane and 8-oxa-6-azabicyclo[3.2.1]octane ring systems under neutral conditions. This reaction can be(More)
Imino sugars of the piperidine and pyrrolidine types can be specifically obtained when protected 5-amino-5-deoxyfuranopentoses, 5-amino-5-deoxyfuranohexoses, 6-amino-6-deoxyfuranohexoses, and 6-amino-6-deoxypyranohexoses undergo a tandem alkoxy radical beta-fragmentation-intramolecular cyclization reaction. The reaction is promoted by the system:(More)
The synthesis of a novel type of branched iminosugars is described. This synthetic strategy is based on two key reactions: first, an aldol reaction with formaldehyde in order to introduce selectively the hydroxymethyl branch, and second, a tandem β-fragmentation-intramolecular cyclization reaction. The combination of both reactions afforded a battery of(More)