Stereoselective Synthesis of Olefins from β‑Hydroxy NHPI Esters

Herein, we describe a highly stereoselective method to access a single olefin isomer from readily available β-hydroxy N-hydroxyphthalimide (NHPI) esters. Depending on the configuration of the precursor (anti or syn), either the E or Z olefin is prepared selectively under Lewis acid-promoted conditions. Without involving radical chemistry, a β-lactone is proposed as the key intermediate in this decarboxylative olefination.