Asymmetric syntheses of the methyl glycosides of 2-deoxy-2-aminohexoses: D-allosamine, D-mannosamine, D-idosamine and D-talosamine
Davies SG., Fletcher AM., Foster EM., Lee JA., Roberts PM., Thomson JE., Waul MA.
© 2014 Elsevier Ltd A range of the methyl glycosides of 2-deoxy-2-aminohexoses, comprising D-allosamine, D-mannosamine, D-idosamine and D-talosamine, were prepared from the corresponding D-aldopentoses via a seven step synthetic sequence. The doubly diastereoselective conjugate addition of the requisite antipode of lithium N-benzyl-N-(α-methylbenzyl)amide and in situ enolate oxidation with the requisite antipode of camphorsulfonyloxaziridine (CSO) was used as the key, stereodefining step. Sequential reduction of the resultant α-hydroxy-β-amino esters and oxidative cleavage of the C(1)–C(2) diol unit furnished the corresponding α-amino aldehydes. Subsequent N- and O-deprotection gave the target compounds (as mixtures of anomers) in good yield and high diastereoisomeric purity.