Visible‐Light Photocatalytic Cyclopropanation of Alkenes with Dibromomethane

The cyclopropane unit plays a crucial role in pharmaceutical compound design and organic transformation. In this study, we have developed a novel redox‐neutral photocatalytic cyclopropanation method involving dibromomethane and alkenes. This chemistry enables the synthesis of valuable functional group‐substituted cyclopropanes using readily available starting materials and practical reaction conditions. Additionally, we have demonstrated the versatility of the products as precursors for various cyclopropane derivatives with different substituents. Importantly, this protocol facilitates the synthesis of a key unit found in a specific type of T‐type calcium channel blocker. Furthermore, the proposed reaction mechanism is well‐supported by control experiments.