Quercus lactones

The homoaldol products (3S,47T)-(Z)-4-hydroxy-3-methyl-l-octenyl and (35, 4/ )-(Z)-4-hydroxy-3,7-dimethyl-l,6-octadienyl diisopropylcarbamate are easily converted into the naturally occurring y-lactones quercus lactone A1073 and ( + )-eldanolide120, respectively. 

Such a sequence has been successfully used115 for the synthesis of 4-methyl-3-heptanol, the major constituent of the aggregation pheromone of the elm bark beetle (Scolytus multistriatus Marsham)117 and zir-butyM-methyltetrahydro-2-furanone118 known as quercus lactone or oak lactone. ... 

The regio- and diastereo-selective reaction of the anion generated from 2-(l-propen-l-yl)-l,3-dithiane with an aldehyde is applicable to the synthesis of rraru-p,y-disubstituted y-lactones, inciting the natural products ( )-eldnolide and ( )-rram-quercus lactone. ... 

The final hydrolysis is not trivial an Hg(II) catalyst is necessary to give acetals 170 that can be oxidised to lactones 171. By this means both syn and anti-172, the quercus lactones from oak bark,45 can be made stereoselectively in 87% and 90% yields respectively. 

Masuda M, Nishimura K 1981 Absolute configurations of quercus lactones, (3R,4i )- and (3S,45)-3-methyl-4-octanolide, from oak wood and chiroptical properties of mono-cyclic y-lac-tones. Chem Lett 1333-1336... 

Methyl-4-octanoUde (whisky-or quercus lactone) Coconut-hke 0 o Alcoholic beverages... 

Wine extracts the quercus lactone (structure cf. S.3.2.3) on storage in oak barrels. The difference in aroma compared with maturation in steel tanks also results fiom oxidative processes, which cause an increase in aldehydes in oak har-... 

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