Scalable, catalytic asymmetric synthesis of anti-,anti-stereotriad building blocks for polypropionate natural products

ORGN 485

Quizhe Xie, qixie@ic.sunysb.edu and Kathlyn A Parker. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400
Abstract: Polypropionate subunits are present in a great number of biological active natural products such as antibiotics, antitumors, antifungals, antiparasitics, or immunomodulators. A widespread strategy to synthesize these structures involves the disconnection of polypropionate chains into shorter subunits, such as stereotriad building blocks bearing alternate methyl and hydroxyl groups. Starting from inexpensive, commercially available starting materials, I developed a powerful protocol to construct anti-, anti-stereotriad building blocks by the catalytic asymmetric synthesis of a chiral trans allylic alcohol, followed by elaboration with the efficient “Midland sequence” (alkylation, 2,3-Wittig rearrangement, protection, and hydroboration).