Synthesis of diverse catechin congeners via diastereoselective intramolecular epoxy-arene cyclization
作者:Runjun Devi、Dimpee Gogoi、Prerona Bora、Sajal Kumar Das
DOI:10.1016/j.tet.2016.06.059
日期:2016.8
4-arylchroman-3-ols with different substitution patterns on both the aromatic rings in high stereo- and regioselectivity via intramolecular epoxy-arene cyclization of 2-(aryloxymethyl)-3-aryloxiranes. The defined protocol is metal-freeusing 20 mol % of p-toluene sulfonic acid monohydrate (TsOH.H2O) as Brønstedacidcatalyst. Depending on the electronic nature of the attacking aromatic ring during the epoxide ring-opening
Friedel–Crafts alkylation of arenes with epoxides promoted by fluorinated alcohols or water
作者:Guo-Xing Li、Jin Qu
DOI:10.1039/b926684d
日期:——
The stereoselective intra- and intermolecular Friedel-Crafts alkylation of electron-rich arenes with epoxides can take place in refluxing 1,1,1,3,3,3-hexafluoroisopropanol owing to its weak acidity and high ionizing power.
Brønsted acid-catalysed intramolecular ring opening of 2-(aryloxymethyl)-3-aryloxiranes leading to trans-4-arylchroman-3-ols: scope and limitations
作者:Runjun Devi、Tapasi Kalita、Sajal Kumar Das
DOI:10.1039/c5ra02193f
日期:——
An operationally simple and metal-free method for the synthesis of a series of trans-4-arylchroman-3-ols via Brønsted acid (TsOH·H2O) catalysed stereoselective intramolecular Friedel–Crafts alkylation of electron-rich arenes by tethered epoxides is developed. The reactions neither need strict anhydrous conditions nor suffer from the use of expensive Lewis/Brønsted acids.