An efficient and green synthesis protocol has been developed for construction of triarylmethane scaffold using trifluoroethanol as a recyclable solvent. Significantly, recyclable solvent and product could be separated by filtration. The expected product could be afforded in good to excellent yield under standard conditions. Meanwhile, recyclable trifluoroethanol solvent could be reused directly for
Metal‐free, Phosphoric Acid‐catalyzed Regioselective 1,6‐Hydroarylation of
<i>para</i>
‐Quinone Methides with Indoles in Water
作者:Biquan Xiong、Lulu Si、Yu Liu、Weifeng Xu、Tao Jiang、Fan Cao、Ke‐Wen Tang、Wai‐Yeung Wong
DOI:10.1002/asia.202200042
日期:2022.5.2
AbstractAn efficient, cheap and green protocol for the highly regioselective 1,6‐hydroarylation of para‐quinone methides (p‐QMs) with indoles at the C‐3 position has been established by phosphoric acid catalysis in water under transition‐metal‐free reaction conditions. A wide range of indole derivatives and para‐quinone methides (p‐QMs) are compatible for the reaction, affording the corresponding 1,6‐hydroarylation products with good to excellent yields. The possible mechanism of the reaction has been explored through step‐by‐step control experiments. The protocol is convenient for practical applications, leading to a safe, green and feasible way for the formation of C‐3 diarylmethyl functionalized indole derivatives.