Unsaturated carbohydrates. Part 27. Synthesis of (–)-exo-brevicomin from a nona-3,8-dienulose derivative

Abstract
The (–)-enantiomer (11) of the insect pheromone (+)-exo-brevicomin has been synthesized directly by hydrogenation–hydrogenolysis of the L-lyxo-nona-3,8-dienulose derivative (10). Epoxide ring opening of the methyl 3,4-anhydro-D-galactopyranoside (6), which was readily obtained from methyl α-D-glucopyranoside, permitted the required configurational inversions at C-3 and C-4