Synthesis of 4‐Acylchromene via Highly Chemoselective Iodine‐Catalyzed Cyclization of Alkynylarylether Dimethylacetals
作者:Warabhorn Rodphon、Charnsak Thongsornkleeb、Jumreang Tummatorn、Somsak Ruchirawat
DOI:10.1002/asia.202000994
日期:2020.11.2
to selective activation of acetal in alkynylarylether dimethylacetal substrates while alkyne moiety remained intact. This activation of acetal led to the generation of oxonium ion intermediate which triggered intramolecular cyclization and elimination of methanol to provide the desired 4‐acylchromene as the sole product in up to 95% yield. Moreover, this method could be applied in a broad range of substrates
4-酰基chrome烯是生物活性天然产物和生物活性合成化合物中的重要核心结构。而且,这种核心结构经常被用作合成更复杂分子的关键前体。在这项工作中,我们发现丙酮和催化性I 2的组合可能导致炔基芳基醚二甲基乙缩醛底物中乙缩醛的选择性活化,而炔烃部分保持完整。乙缩醛的这种活化导致产生氧离子中间体,从而引发分子内环化并消除了甲醇,从而以高达95%的收率提供了所需的4-酰基色烯作为唯一产品。此外,该方法可在温和且无金属的催化条件下用于广泛的底物,用于合成4酰基色烯衍生物。