Stereoselective Synthesis

Abstract

This chapter discusses total stereoselective synthesis of acetogenins of a new class of bioactive polyketides named Annonaceae. Annonaceae, a family of tropical and subtropical trees, are known by populations of South America either for their edible fruits (for species of the Armona genus) or for their uses in traditional medicine as pesticide, antiparasite, etc. The total synthesis of acetogenins of Annonaceae remains a challenging goal for synthetic chemists. Indeed, despite their relatively simple structures, these new natural compounds possess a large number of stereogenic centers (5 to 10), for which the stereocontrolled formations require many steps. Therefore, shorter and easier synthetic pathways are still needed for rapid, efficient, and scale up preparations. The asymmetric syntheses are based on two different approaches—namely: (1) stereospecific strategies using as starting material a compound from the chiral pool (a-amino acids, sugars) and (2) asymmetric induction using homochiral catalysts (Sharpless' epoxidation, Sharpless' asymmetric dihydroxylation).