奥西多尔
钯
化学
炔丙基
亲核细胞
吲哚试验
色胺
亲核加成
级联反应
药物化学
催化作用
组合化学
有机化学
立体化学
生物化学
色胺
作者
Antoinette E. Nibbs,Thomas D. Montgomery,Ye Zhu,Viresh H. Rawal
标识
DOI:10.1021/acs.joc.5b00277
摘要
Reported here are methods for the direct construction of a range of spirocyclized oxindoles and indolenines in good to excellent yields. Specifically, we report the palladium-catalyzed reactions of oxindoles and indoles, both functioning as bis-nucleophiles, with propargyl carbonates to afford spirocyclic products having an exocyclic double bond on the newly formed ring. The reaction proceeds through a process wherein the first nucleophilic unit on the oxindole or indole reacts with an allenyl-palladium species, formed from oxidative addition of Pd(0) to propargyl carbonates, to generate a π-allyl palladium intermediate that then reacts further with the second nucleophilic component of the oxindole or indole. The cascade process forges two bonds en route to spirocyclized oxindole and indolenine products. The use of chiral phosphines renders the cyclization sequence enantioselective, providing spirocyclic products with modest to good enantioselectivities.
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