Tin Tetrachloride-Catalyzed Regiospecific Allylic Substitution of Quinone Monoketals: An Easy Entry to Benzofurans and Coumestans
作者:Yingjie Liu、Jingxin Liu、Mang Wang、Jun Liu、Qun Liu
DOI:10.1002/adsc.201200344
日期:2012.10.8
A highly regioselective allylic substitution of quinone monoketals with α-oxoketene dithioacetals is achieved under the catalysis of only tintetrachloride (1 mol%). The advantages of the reaction, including its simplicity, rapidity, low catalyst loading of inexpensive tintetrachloride, mild conditions and; in particular, the regiospecificity, is proposed to be due to a pseudo-intramolecular process
A concise and efficient approach to the syntheses of coumestan analogues has been developed. The underpinning strategy involves a FeCl3-mediated direct intramolecular oxidative annellation of 4-hydroxy-3-phenyl-2H-chromen-2-one derivatives. Utilizing this synthetic protocol, a variety of coumestan derivatives were conveniently obtained from readily available reagents.
Catecholase-catalyzed synthesis of wedelolactone, a natural coumestan and its analogs
作者:Anushree Achari、Sourav Chatterjee、Sudip Dey、Tapas K. Kundu、Parasuraman Jaisankar
DOI:10.1039/d2ob02081e
日期:——
Biocatalysis plays an important role in the synthesis of complex organic molecules. Wedelolactone, a natural coumestan, has been reported to have many bioactive properties. A novel and efficient enzyme obtained from sweet potato juice was used for condensation of 4-hydroxycoumarins with catechols to produce wedelolactone and its structurally diverse analogs in moderate to good yields under mild reaction