Photocatalytic Isomerization of Styrenyl Halides: Stereodivergent Synthesis of Functionalized Alkenes

An efficient and general method for the isomerization of styrenyl halides under different photocatalytic conditions ( fac ‐Ir(ppy) 3 in methanol for E to Z isomerization and fluorescein in 1,4‐dioxane for Z to E isomerization, respectively) is disclosed. A series of stereospecific transformations constitute preliminary validation of this strategy in the synthesis of functionalized alkenes, including two diaryl alkenes, a styrenyl boronic ester and an enyne. The photocatalytic isomerization and subsequent cross coupling reaction can be run in a one‐pot manner. The stereodivergent synthesis of all four isomers of a conjugated diene, as well as the antitumor agent DMU‐212 and its ( Z )‐isomer highlights the synthetic applicability of this method.