corresponding N-substituted dimethyl 3-oxoisoindolin-1-ylphosphonates in good yield which, by means of a dephosphonylation reaction with lithiumaluminum hydride, give the target N-substituted isoindolin-1-ones in moderate to good yield. amino phosphonates - isoindolinones - C-P cleavage - microwave irradiation - one-pot reaction