ACYLKETENE ACETALS IN ORGANIC-SYNTHESIS

The preparation and reactivity of achiral and enantiomerically pure acylketene acetals are described. The key reactions of these substrates involve facile conjugate hydroboration and organolithium addition. Enantiomerically pure acylketene acetals were employed to generate a homochiral beta-keto ketal through a highly diastereoselective lithium enolate quench. This beta-keto ketal, which was also prepared through a desymmetrization ketalization reaction on a meso dione, was employed in the synthesis of the insect pheromone sitophilure.