Hydriodic acid-mediated cyclization of a-substituted secondary 2-ethenylbenzamides: Synthesis of 2-substituted 2,3-dihydro-3,3-dimethyl-1H- isoindol-1-ones and 3,3-disubstituted (E)-1-(arylimino)-1,3- dihydroisobenzofurans

摘要

A new and facile method for the preparation of 2-substituted 2,3-dihydro-3,3-dimethyl-1H-isoindol-1-ones 3 and 3,3-disubstituted (E)-1-(arylimino)-1,3-dihydroisobenzofurans 6 has been developed. Thus, treatment of N-alkyl(or aryl)-2-(1-methylethen-1-yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3. Similar treatment of N-aryl-2-(1-phenylethen-1-yl)benzamide 5 with concentrated HI at 0° afforded 6.