A Simple and Mild Synthesis of 1H-Isochromenes and (Z)-1-Alkylidene-1,3-dihydroisobenzofurans by the Iodocyclization of 2-(1-Alkynyl)benzylic Alcohols

Supplemental Files
Date
2009-12-31
Authors
Mancuso, Raffaella
Mehta, Saurabh
Gabriele, Bartolo
Salerno, Giuseppe
Jenks, William
Larock, Richard
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Chemistry
Organizational Unit
Journal Issue
Series
Abstract

A variety of iodo-substituted isochromenes, dihydroisobenzofurans, and pyranopyridines are readily prepared in good to excellent yields under mild conditions by the iodocyclization of readily available 2-(1-alkynyl)benzylic alcohols or 2-(1-alkynyl)-3-(hydroxymethyl)pyridines. Reactions are carried out in MeCN at 25 °C with 3 equiv of I2 as the iodine source and NaHCO3 (3 equiv) as the base. The regiochemical outcome of the reaction strongly depends on the substitution pattern of the starting material. In particular, the 5-exo-dig cyclization mode, leading to dihydroisobenzofurans, is observed in the case of substrates bearing a tertiary alcoholic group, owing to the gem-dialkyl effect, while the 6-endo-dig cyclization mode, leading to isochromene or pyranopyridines, is the usually preferred pathway in the case of substrates bearing a primary or secondary alcoholic group.

Description

Reprinted (adapted) with permission from The Journal of Organic Chemistry, 75(3); 897-901. Doi: 10.1021/jo902333y. Copyright 2009 American Chemical Society.

Keywords
Citation
DOI
Collections