Highly efficient intramolecular cyclizations of 2′-hydroxychalcones to 4-chloro-2<i>H</i>-chromenes under vilsmeier conditions
作者:Zhen-Hua Li、Cun Zheng、Wei-Ke Su
DOI:10.1002/jhet.5570450441
日期:2008.7
Highlyefficientintramolecularcyclization and of 2′-hydroxychalcones to 4-chloro-2H-chromenesunderVilsmeierconditions have been developed. In comparison with the reported methods, studies carried out indicate that Vilsmeier reagent generated in situ from DMF and bis(trichloromethyl) carbonate (BTC) provides excellent chemselectivity, higher yields and avoids the formation of inorganic phosphorus