Titanium Tetrachloride‐Mediated Approach to Access 2‐Chloro‐2‐Substituted Isoindolin‐1‐ones through the Addition of Alkynes to Acyliminium ions

An asymmetric approach to access 2‐substituted isoindolin‐1‐ones 9–11 was developed through TiCl4‐mediated addition‐chlorination of N,O‐acetals 7 a–7 c with terminal alkynes 8. A range of substrates were amenable to this transformation, and the desired substituted isoindolin‐1‐ones were obtained in moderate to good yields with moderate diastereoselectivities.