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

Hui-Lin Mao, Jun Yu, Yi-Ting Shen, Qiuyun Li,* Wen-Juan Hao,* Bo Jiang*

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.

Adv. Synth. Catal. 2023, 365, 3075-3081; DOI:10.1002/adsc.202300674