Synthesis of 3-substituted 8-hydroxy-3,4-dihydroisocoumarins via successive lateral and ortho-lithiations of 4,4-dimethyl-2-(o-tolyl)oxazoline
作者:Naruki Tahara、Tsutomu Fukuda、Masatomo Iwao
DOI:10.1016/j.tetlet.2004.04.158
日期:2004.6
of 4,4-dimethyl-2-(o-tolyl)oxazoline in THF with sec-BuLi, aromatic or aliphatic aldehydes, sec-BuLi, B(OMe)3, and H2O2 produced the laterally alkylated and ortho-hydroxylated oxazolines in one-pot. Treatment of these products with TFA in aqueous THF provided 3-substituted 8-hydroxy-3,4-dihydroisocoumarins in 44–75% overall yields. This procedure allowed the short synthesis of (±)-hydrangenol and (±)-phyllodulcin
用仲-BuLi,芳族或脂族醛,仲-BuLi,B(OMe)3和H 2 O 2依次处理THF中的4,4-二甲基-2-(邻甲苯基)恶唑啉,生成侧烷基化和邻位一锅中的-羟基化的恶唑啉。用TFA在THF水溶液中处理这些产品可提供3-取代的8-羟基-3,4-二氢异香豆素,总产率为44-75%。该方法允许短合成(±)-羟基和(±)-叶绿素,它们是天然存在的具有药理学意义的3,4-二氢异香豆素。还描述了通过三阴离子中间体更经济地合成(±)-叶绿素。