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Convenient and Highly Efficient Routes to 2 H ‐Chromene and 4‐Chromanone Derivatives: Iodine‐Promoted and p ‐Toluenesulfonic Acid Catalyzed Cascade Cyclizations of Propynols
Author(s) -
Qiu YiFeng,
Ye YuYing,
Song XianRong,
Zhu XinYu,
Yang Fang,
Song Bo,
Wang Jia,
Hua HuiLiang,
He YuTao,
Han YaPing,
Liu XueYuan,
Liang YongMin
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201406100
Subject(s) - catalysis , chemistry , combinatorial chemistry , halide , p toluenesulfonic acid , cascade , reaction conditions , iodine , palladium , organic chemistry , chromatography
Abstract A convenient strategy is presented for the easy preparation of a series of 2 H ‐chromenes under mild conditions through iodocyclization of readily accessible propynols. In addition, various 4‐chromanones can be synthesized through a p ‐toluenesulfonic acid catalyzed cascade cyclization with high efficiency (yields up to 99 %). Our developed reaction systems are proven to have good functional‐group applicability and can be scaled up to gram quantities in satisfactory yields. These systems also provide a new synthetic strategy for two types of important flavonoid skeleton without using costly and toxic metal catalysts. Additionally, the resulting halides could be further exploited in subsequent palladium‐catalyzed coupling reactions, so these compounds could act as potential intermediates for the construction of some valuable drug molecules.