An efficient methodology for the synthesis of 2-C-branchedglyco-aminoacid derivatives by diastereoselective ringopening of 1,2-cyclopropanecarboxylatedsugars in good yields is reported. [reaction--see text]
A stereoselective methodology was developed for the construction of C-spiro-glycosides in two steps involving bromonium ion activated solvolytic ring opening of sugar derived 1,2-cyclopropanecarboxylates followed by a one-pot dehydrohalogenation, intramolecular hetero-Michael addition (IHMA) and ester hydrolysis. The obtained spirocyclic lactols were further converted to enantiomerically pure spirolactones.
theory: 1,2‐Cyclopropanecarboxylated sugars were used as glycosyl donors for the first time in the synthesis of 2‐C‐branched oligo(glyco–aminoacid)s (OGAAs; see scheme) decorated with α‐amino acids. The method was applied to an acceptor‐reactivity‐based stereo‐ and regioselective glycosylation reaction towards the preparation of several disaccharide‐derived glyco–aminoacid derivatives.
[structure: see text]. An efficient method has been developed for the construction of fused perhydrofuro[2,3-b]pyrans by diastereoselective ring opening of 1,2-cyclopropanated sugar derivatives. The methodology has been successfully applied to the synthesis of fused perhydrofuro[2,3-b]pyrano-gamma-butyrolactone derivatives.