Structures of Two C13-Norisoprenoid Glucosidic Precursors of Wine Flavor

ABSTRACT The β-D-glucopyranosides of (3R,8E)-3-hydroxy-β-damascone and (6R,7E,9R)-3-oxo-α-ionol have been characterized in a Riesling wine glycosidic extract by means of GC/MS analysis of their trifluoroacetylated derivatives and synthesis of authentic racemic compounds. The absolute configurations were determined by 1H-NMR spectros-copy of the diastereomeric esters prepared from (R)-2-phenyl propionic acid and racemic (E)-3-hydroxy-β-damascone and by comparison with (6R,7E,9R)-3-oxo-α-ionol extracted from tobacco. These two glucosides were also identified in wines and grapes from other Vitis vinifera cultivars