Photocatalytic Cascade Trifluoromethylation/Cyclization : Selective Synthesis of Trifluoroethylated Benzopyran and Benzopyranone Derivatives

Abstract

We have realized the photocatalytic radical cascade cyclization reaction, enabling the one‐step synthesis of rare trifluoroethyl benzopyran derivatives with a wide variety of structures and excellent yields. Furthermore, the approach exhibits low catalyst load, strong regional control and wide applicability under mild conditions. The selectivity of this transformation is influenced by the length of the carbon chain of the benzaldehyde, as demonstrated by the density functional theory calculations. Additionally, scaling up the photocatalytic process can be easily accomplished.