A highly efficient and stereoselective synthesis of coumarin-, 1,3-cyclohexanedione-, and 1,4-naphthoquinone-fused 2,8-dioxabicyclo[3.3.1]nonanes is described. This was achieved via a sequential Michael addition/bicyclizationreaction from easily accessible 3-(2-hydroxyphenyl)-1-phenylprop-2-en-1-one derivatives. Three chemical bonds (one C–C bond and two C–O bonds), two six-membered cycles, and two
Asymmetric Synthesis of 3,4-Dihydrocoumarins Bearing an α,α-Disubstituted Amino Acid Moiety
作者:Joanna Hejmanowska、Anna Albrecht、Jakub Pięta、Łukasz Albrecht
DOI:10.1002/adsc.201500598
日期:2015.12.14
An organocatalytic approach for the stereoselective synthesis of 3,4-dihydrocoumarins with an α,α-disubstituted amino acid moiety incorporated is presented. The developed methodology is based on the cascade reaction between α-substituted azlactones and 2-hydroxychalcones. It is initiated by a chiral Brønsted base-catalyzed enantio- and diastereoselective Michael reaction followed by the azlactone ring
Diastereoselective construction of 4-indole substituted chromans bearing a ketal motif through a three-component Friedel–Crafts alkylation/ketalization sequence
作者:Jiao-Mei Guo、Wen-Bo Wang、Jia Guo、Yan-Shuo Zhu、Xu-Guan Bai、Shao-Jing Jin、Qi-Lin Wang、Zhan-Wei Bu
DOI:10.1039/c8ra02481b
日期:——
TfOH-catalyzed three-component Friedel–Crafts alkylation/ketalization sequence of indoles, alcohols and ortho-hydroxychalcones was developed to afford a wide range of 4-indole substituted chromans bearing a ketal motif in 77–99% yields. Notably, only a simple filtration was needed to purify them. By altering methanol to CHCl3, 2,4-bisindole substituted chroman with the same indole substituent at the