Rhodium-catalysed nucleophilic ring opening reaction of 1-and 3-ethoxy-5,8-epoxy-5,8-dihydroisoquinolines

Abstract

2-Ethoxy-3- and 5-chloropyridines were obtained from 2,3- and 2,5-dichloropyridine. Reaction of 2,3- and 2,5-dichlo-ropyridines with tBuLi in the presence of furan gave 1- and 3-ethoxy-5,8-epoxy-5,8-dihydroisoquinolines. The rhodium-catalysed ring-opening reaction of 1- and 3-ethoxy-5,8-epoxy-5,8-dihydroisoquinolines with 2-bromophenol furnished the isomer 7-(2-bromophenoxy)-1-ethoxy-7,8-dihydroisoquinolin-8-ol, 6-(2-bromophenoxy)-1-ethoxy-5,6-dihydroisoquinolin-5-ol and 7-(2-bromophenoxy)-3-ethoxy-7,8-dihydroisoquinolin-8-ol, 6-(2-bromophenoxy)-3-ethoxy-5,6-dihydroisoquinolin-5-ol respectively.