A New Approach to Dihydrobenzofurans and Dihydrobenzopyrans (Chromans) Based on the Intramolecular Trapping by Alcohols of Benzynes Generated from 7-Substituted-1-aminobenzotriazoles
作者:Michael A Birkett、David W Knight、Paul B Little、Michael B Mitchell
DOI:10.1016/s0040-4020(00)00021-1
日期:2000.2
1-Aminobenzotriazoles 9 having 7-hydroxyalkyl substituents are efficiently converted into the corresponding benzynes 4 when treated with N-iodosuccinimide which then undergo highly efficient intramoleculartrapping by the pendanthydroxylgroups leading to dihydrobenzofurans 24–26 and dihydrobenzopyrans (chromans) 27, with incorporation of a synthetically useful iodine atom adjacent to the new ether bond, which allows