A new synthetic route towards iminosugars starting from chiral epoxyamides is described. The strategy, by which a single precursor, the α,β-epoxyamide obtained from 6-O-trityl-2,3-O-isopropylidene-d-ribose and a sulphur ylide, can be transformed into different iminosugars, is based on the combination of a regioselective epoxide opening and stereospecific intramolecular displacements.
This paper describes a new synthetic route towards hydroxylated pyrrolidines and azepane derivatives starting from chiral epoxyamides. The alternate transformations on a ribose derivative α,β-epoxyamide permit the construction of five or seven member rings leading to different precursors of homoiminosugars.
Azido group reduction was observed by the treatment of a 2-azido-3-triisopropylsilyloxy heptonamide derivative with NaI in DMSO. The process allowed us to obtain a tetrahydroxypipecolic acid amide derivative. The same azido amide was treated with LiCl in DMSO, but desilylation occurred to give 3,6-anhydro-2-azido heptonamide. (C) 2008 Elsevier Ltd. All rights reserved.