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To date, the enzymatically-catalysed synthesis of pentose-containing compounds has been limited to the production of oligo-β-(1 → 3) and oligo-β-(1 → 4)-linked xylopyranosides. To our knowledge, no such syntheses have involved arabinofuranose or, indeed, any other sugars in the furanose configuration. In this report, we describe the use of a thermostable α-l-arabinofuranosidase for the synthesis of p-nitrophenyl α-l-arabinofuranosyl-(1 → 2)-α-l-arabinofuranoside, p-nitrophenyl β-d-xylopyranosyl-(1 → 2)-β-d-xylopyranoside, p-nitrophenyl β-d-xylopyranosyl-(1 → 3)-β-d-xylopyranoside and benzyl α-d-xylopyranosyl-(1 → 2)-α-l-arabinofuranoside. Importantly, this latter compound is synthesised in a highly regiospecific reaction, which leads to the production of a single disaccharide. [Copyright &y& Elsevier]

Abstract: A convenient approach to the construction of dihydroxylated unsaturated azepanes featuring a functional group (ethoxycarbonyl)methyl or (cyano)methyl at C-2 was achieved from a pent-4-enal synthon obtained in four steps from d-xylose. The key step of the sequence relied on the conjugate addition of allylamine to α,β-unsaturated ester or nitrile, prepared by Wadsworth–Emmons olefination. Subsequent RCM afforded the target unsaturated azepanes. [Copyright &y& Elsevier]

A thermostable α-l-arabinofuranosidase was tested for its ability to perform transglycosylation with different alcohol acceptors. Reactions were characterized by high rates with optimal synthesis being obtained within 10 min. Both primary and secondary alcohols could act as acceptors in transarabinosylation but yields of alkyl arabinosides decreased with increasing alkyl chain length. [Copyright &y& Elsevier]

Review: 260 refs. [ABSTRACT FROM AUTHOR]

Key steps in the synthesis of azepanes (VIII) and (X), which are of interest as glycosidase inhibitors, are the conjugate addition of allylamine to the precursor (III) and final ring-closing metathesis with the pure diastereomers (VII) and (IX). [ABSTRACT FROM AUTHOR]