Total Synthesis of Eupomatilones 1, 2, and 5 by Enantioselective [2,3]‐Wittig Rearrangement

Abstract

AbstractIn this study, the asymmetric total synthesis of eupomatilones 1, 2, and 5 has been accomplished. These compounds are lignan congeners containing a biaryl system bearing an α‐methylene γ‐lactone. They were isolated from the Australian shrub Eupomatia bennettii. Two chiral centers were constructed enantioselectively by the asymmetric [2,3]‐Wittig rearrangement of highly oxygenated biaryl compounds, using a bis(oxazoline) chiral ligand. Optimization of the key reaction using nBuLi as the base and ether as the co‐solvent increased the enantioselectivity to 88–91 % ee.