A DIASTEREOSELECTIVE SYNTHESIS OF BOTH QUERCUS LACTONE ISOMERS EMPLOYING ALLYL-TYPE ORGANOMETALLICS AS KEY INTERMEDIATES

Article abstract of DOI:10.1016/S0040-4039(01)81474-X

Consecutive treatment of endo-butenyl potassium or endo-1-(tetrahydropyranyloxy)-exo-butenyl lithium with fluorodimethoxyboron and pentanal at -75 deg C affords an erythro- and, respectively, threo-adduct, the hydrolysis and oxidation of which leads to the cis- and,respectively, trans-isomer of 5-butyl-4-methyl-tetrahydro-2-furanone (4-butyl-3-methyl-4-butanolide), 1, the so called quercus or oak lactones.