Visible light-induced aerobic photooxidative cleavage of C(sp3)–C(sp2) σ-bonds of allylarenes†

The development of the C–C bond cleavage of allylarenes is of vital importance. However, the cleavage of C(sp³)–C(sp²) σ-bonds has been rarely reported previously. Herein, we disclose an efficient and green photooxidative cleavage of C(sp³)–C(sp²) σ-bonds of allylarenes under the irradiation of blue LEDs using anthraquinone (AQ) as the photocatalyst and eco-friendly molecular oxygen (O₂) as the sole oxidant. The newly developed reaction shows broad substrate scopes under metal- and additive-free conditions, providing practical and scalable access to aromatic aldehydes and ketones. Preliminary mechanistic studies suggest that a delocalized allylic radical generated via a hydrogen atom transfer (HAT) between photoexcited AQ (AQ*) and the allylic C(sp³)–H bond might be involved in this transformation.