Regioselective Pd-catalyzed alkylations of 3,5-dibromo-2-pyrone and application toward short synthesis of supellapyrone

Abstract

Supellapyrone is the female sex pheromone of the brownbanded cockroach (Supella longipalpa), isolated by Roelofs and coworkers in 1993. The relative and absolute stereochemistry was subsequently determined (2R,4R)-y by Meinwald and coworkers in 1995 with chemical synthesis and chromatographic comparison to the authentic sample. Envisioned that both 2-pyrone core and side chain can be readily prepared from 3,5-dibromo-2-pyrone, we prepared the 2-pyrone intermediate 2 and 3 through Pd-catalyzed coupling reactions with Me3Al. Subsequent operation including asymmetric hydrogenation of 4 provided 5, which was coupled with 2 under the Negishi coupling protocol to afford supellapyrone in highly efficient way