Substituent‐Controlled Regiodivergent Palladium‐Catalyzed Annulative Dearomatization of Phenols toward Skeletally Diverse Spirocyclohexadienones

Abstract A palladium‐catalyzed intermolecular dearomative formal [4+2] annulation of phenols with propargyl electrophiles is reported, enabling substituent‐controlled regiodivergent synthesis of a wide range of skeletally diverse spirocyclohexadienones with good yields. The regiodivergence could be precisely controlled by adjusting the steric hindrance of O ‐ and N ‐substituents from binucleophilic substrates, where substrates with an O ‐nucleophilic site were converted into spiro[chromane‐4,1′‐cyclohexane]‐2′,5′‐dien‐4′‐ones with complete regioselectivity and ( Z )‐selectivity, whereas N ‐nucleophiles enabled a different regiodivergent process to access spiro[cyclohexane‐1,4′‐quinoline]‐2,5‐dien‐4‐ones.