Novel heterocyclic ring-expansion and/or dehydration-hydration reactions of propargylic and allenylic hydroxy γ-lactams in the presence of strong base or Lewis acid

Dehydration-hydration products were obtained in good yields by the treatment of propargylic hydroxy γ-lactams with some Lewis acids. Several propargylic and allenylic hydroxy γ-lactams were successfully converted to the corresponding ring-expanded benzazepines in various yields via a tandem decyclization-cyclization process in the presence of (TMS)2NLi, (TMS)2NNa, or n-BuLi under reflux conditions in THF.