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Lewis‐Base‐Catalyzed Alkylation Reaction of 4‐Hydroxycoumarins with Allenoates: Regioselective Synthesis of 2 H ‐[3,2‐c] Furocoumarins and 4‐Hydroxycoumarin Vinyl Ether Derivatives
Author(s) -
Su Qiuling,
Qian Houjun,
Li Zhengyi,
Sun Xiaoqiang,
Wang Zhiming
Publication year - 2017
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201600631
Subject(s) - chemistry , regioselectivity , furocoumarins , alkylation , 4 hydroxycoumarin , catalysis , vinyl ether , lewis acids and bases , ether , organic chemistry , addition reaction , medicinal chemistry , photochemistry , copolymer , polymer
A milder, more regioselective and practical approach to C 3 or O‐alkylation reaction of 4‐hydroxycoumarins has been established. Both 2 H ‐[3,2‐c] furocoumarins and 4‐hydroxycoumarin vinyl ether derivatives could be efficiently prepared by alkylating 4‐hydroxycoumarins with electron‐deficient allenoates catalyzed by PPh 3 and DBU, respectively. The reaction outcomes can be controlled by changing the catalysts, starting with the same reaction substrates. Possible reaction mechanisms have also been proposed