Solid-phase synthesis of indol-2-ones by microwave-assisted radical cyclization

Article abstract of DOI:10.1055/s-2004-820052

Solid-phase synthesis of indol-2-ones (2-oxindoles) by means of aryl radical cyclization of resin-bound N-(2-bromophenyl)acrylamides using Bu ₃SnH is described. Among various solvents tested, DMF was found to be the best choice for the radical cyclization inducing a reagent concentration effect of the polymer support. The reaction proceeded smoothly under microwave irradiation to give the desired indol-2-ones within a very short reaction time in comparison to conventional thermal heating. In this reaction, various indol-2-ones were synthesized by using commercially available 2-bromoanilines and acryloyl chloride derivatives.