Diastereoselective access to chiral non‐racemic [1,3]oxazolo‐[2,3‐a]isoindol‐5‐one ring systems viaO‐cationic cyclization

Dedicated to Professor Jean Morel for his retirement The title compounds 4 have been prepared from suitable β‐amino‐ alcohol 2 and phthalic anhydride (5) in a three‐step sequence in moderate to good yields (58‐94%). The key step of this methodology is based on an intramolecular O‐cationic cyclization involving N‐acyliminium species. The high levels of the observed chemoselectivity during the intermolecular or intramolecular cyclization were also discussed.