High-precision asymmetric synthesis of stegobiol and stegobinone via boronic esters

Abstract

Highly stereoselective boronic ester chemistry has been used to synthesize the drugstore beetle pheromones stegobiol and stegobinone. The convergent route utilizes a single intermediate, 2-(3-benzyloxy-1-chloro-2-methylpentyl)-4,5-dicyclohexyl-1,3,2-dioxaborolane, containing all of the stereogenic centers for both segments of the pheromones, 3-benzyloxy-2-methylpentanal and 5-(t-butyldimethylsiloxy)-4-methylhexan-4-one, requires only one chromatographic separation, and is the first synthesis to provide pure, crystalline samples