Piecewise Stereoselective Assembly of Multisubstituted Alkenes

-dibromoolefins to address the limited availability of stereodefined alkenyl bromides. In the presence of a phthalimide additive, selective monofunctionalization enables access to over 40 stereodefined alkenyl bromides, providing a general and stereoselective pathway to these otherwise difficult-to-access intermediates. Direct access to alkenyl bromides enables piecewise stereoselective assembly of multisubstituted alkenes through sequential alcohol coupling or stereoretentive Suzuki-Miyaura reactions. These strategies are illustrated via iterative cross-coupling sequences and the total synthesis of (+)-sponalisolide B.