Synthesis of isoindolo[1,3]benzoxazine derivatives through intramolecular arylation of N‐ acyliminium ions

[1,3]Benzoxazines annulated to isoindole as 3 and 4 have been synthesized in three steps from N ‐chloromethylphthalimide 5 and substituted phenols 6 . The key step was the acid‐catalyzed cyclization of ω‐carbinol lactams 8 and 9.