A second-generation synthesis of Leucascandrolide A

ORGN 691

Lori Jean Van Orden, lvanorde@uci.edu, Brian D. Patterson, and Scott D. Rychnovsky, srychnov@uci.edu. Department of Chemistry, University of California, Irvine, Irvine, CA 92617

Leucascandrolide A is a macrolide believed to be isolateed from adventitious bacteria found in Leucascandra caveolata, a calcareous sponge from the Coral Sea. Due to its high inhibition (IC50 values of 0.25 to 0.05 µg/mL) of human cancer cell proliferation and yeast growth (Candida albicans), Leucascandrolide A has been a target of interest for nine research programs to date. Our first generation synthesis utilized a key Mukaiyama aldol-Prins (MAP) reaction, methodology developed in our group, which set two stereocenters. Our second generation synthetic strategy also relies on a MAP reaction but has now been engineered to set three stereocenters simultaneously. This modification has allowed for a more concise synthesis.