Gold-Catalyzed Photoredox C(sp2) Cyclization: Formal Synthesis of (±)-Triptolide

Photoexcitation of ditheric gold Complex showed the activation of a C(sp(2)) -Br bond to generate a vinyl radical in a mild photoredbx catalysis process. Use of [Au-2(dppm)2] Cl-2 with 365 nm LEDs in a photoredox catalysis process to produce polycyclic scaffolds using vinyl radicals is reported. This method achieved the synthesis of a small library of butenolide polycyclic compounds and naphthol polycyclic compounds. The efficacy of this photoredox process was further demonstrated by accomplishing the concise formal synthesis of (+/-)-triptolide.