Photoinduced synthesis of C2-linked phosphine oxides radical difunctionalization of acetylene

Herein, we report a photocatalyzed radical difunctionalization of acetylene for the rapid synthesis of C2-linked phosphine compounds. The reaction was initiated by addition of a phosphinoyl radical, followed by two cascade transformations. One involves a double addition for the formation of DPPE-dioxide analogues and in the other the intermediate vinylphosphine oxide is intercepted by a radical formed from an oxoheterocycle. This method features metal-free and mild conditions (rt, 1 atm acetylene), 100% atom economy and easy operation. Furthermore, the reaction can be robustly performed on a decagram scale. A photocatalyzed radical difunctionalization of acetylene was achieved, which enables the green synthesis of C2-linked phosphine oxides.