VOLATILE NORISOPRENOID COMPOUNDS AS CONSTITUENTS OF OAK WOODS USED IN WINE AND SPIRIT MATURATION

Thirty-one norisoprenoid compounds have been identified for the first time in model wine extracts of American and Vosges oak woods. Only one compound of this type, β-ionone, had been previously reported as an oak constituent. The four isomeric 3, 4-dihydro-3-oxoactinidols [i.e., isomers of 2, 2, 6-trimethyl-8-(1-hydroxyethyl)-7-oxabicyclo[4.3.0]non-9-en-4-one], (E)- and (Z)-9-hydroxymegastigma-4,6-dien-3-one, 9-hydroxymegastigm-4-en-3-one (blumenol C), and two diastereomers of each of the two oxoedulan derivatives 2,3,5,6,8,8a-hexahydro-2,5,5,8a-tetramethyl-7H-1-benzopyran-7-one and octahydro-2,5,5,8a-tetramethyl-7H-1-benzopyran-7-one were found at a collective concentration of 11.6 mg/kg of wood in the American sample but were either absent or found at low concentrations only in the French timber. The Vosges oak yielded 9-hydroxymegastigm-5-en-4-one and two diastereomers of 2,6,10,10-tetramethyl-1-oxaspiro[4,5]decan-7-one as significant constituents. Most of the newly recognized oak norisoprenoids have been previously identified in grape products, thus further linking the compositions of oak and wines. The work reports, for the first time, 5S*,6R*-9-hydroxymegastigm-7-en-3-one and (tentatively) 9-hydroxymegastigman-3-one as natural products. © 1990, American Chemical Society. All rights reserved.