o-Phenylenediacetic Acid Anhydride in the Castagnoli-Cushman Reaction: Extending the Product Space to ε-Lactams

The diversity of lactam products accessible by the Castagnoli-Cushman reaction (CCR) of imines and dicarboxylic acid anhydrides has been extended to privileged epsilon-lactams. This novel variant of the CCR using o-phenylenediacetic anhydride is often high-yielding and remarkably diastereoselective and allows the use of alpha-C-H imines.