The stereoselective transformation of the cyclopropyl derivative 2, stereoselectively obtained with the Simmons–Smith reaction of methyl 2,6-di-O-benzyl-α-l-threo-hex-4-enopyranoside (1), into gabosines and deoxy-carbahexoses is described. The treatment of 2 with mercuric trifluoroacetate in dry methanol gives the organomercuric chloride 3, which by demercuration with lithium aluminum hydride affords the 4-C-deoxy-4-methyl-1,5-bis-glycoside 4. The acid hydrolysis of 4 produces a mixture of the two diastereoisomeric 2-methyl-cyclohex-2-enones 6 and 7, catalytically reduced to carba-sugars 10 and 11. Structures and stereochemistry of all isolated compounds were determined by 1D and 2D NMR experiments

A new Method for the Synthesis of Carba-sugars Enones (Gabosines) Using a Mercury(II)-Mediated Opening of 4,5-Cyclopropanated Pyranosides as the Key-step

CORSARO, Antonino;CHIACCHIO, MARIA ASSUNTA ROSSELLA;PISTARA', Venerando
2006

Abstract

The stereoselective transformation of the cyclopropyl derivative 2, stereoselectively obtained with the Simmons–Smith reaction of methyl 2,6-di-O-benzyl-α-l-threo-hex-4-enopyranoside (1), into gabosines and deoxy-carbahexoses is described. The treatment of 2 with mercuric trifluoroacetate in dry methanol gives the organomercuric chloride 3, which by demercuration with lithium aluminum hydride affords the 4-C-deoxy-4-methyl-1,5-bis-glycoside 4. The acid hydrolysis of 4 produces a mixture of the two diastereoisomeric 2-methyl-cyclohex-2-enones 6 and 7, catalytically reduced to carba-sugars 10 and 11. Structures and stereochemistry of all isolated compounds were determined by 1D and 2D NMR experiments
4,5-cyclopropanated sugars; intramolecular aldol condensation; gabosines; 6-deoxy-5a-carba-hexopyranosides
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/9035
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