The tricyclic core of marine natural products schulzeines was synthesized using N-acyliminium ion cyclization. The intermediate N-acyliminium ion was generated from treatment of alpha-hydroxy-delta-lactam with a Lewis acid. The tricyclic products were obtained as a mixture of 2 diastereomers at the C-11b stereocenter. The diastereomeric ratios were low and dependent on the Lewis acid used in the reaction.