Metal‐Free Visible Light‐Promoted Synthesis of 1,2,2‐Triarylethanones and 2,2‐Diarylethanones: Route Towards Tamoxifen

Abstract An efficient and straightforward methodology for the synthesis of 1,2,2‐triarylethanones and 2,2‐diarylethanones has been developed, via a visible light‐promoted/Brønsted acid‐catalyzed carbonyl‐alkyne metathesis/transfer hydrogenation one‐pot reaction of benzoquinone, arylalkyne, and Hantzsch ester. A series of synthetically useful triarylethanones and diarylethanones were achieved in excellent yield under mild reaction conditions. This protocol is operationally simple, photocatalyst‐free, and scalable and has a broad substrate scope. Moreover, this reaction involves the formation of three chemical bonds, namely C=O, C−C, and C−H bonds. This feature enables de novo synthesis of 1,2,2‐triarylethanones and 2,2‐diarylethanones. Additionally, this protocol provides a convenient and practical synthetic route for tamoxifen.