2,6-Diphenyl-3-(prop-2-en-1-yl)piperidin-4-one.

In the title compound, C20H21NO, the dihedral angle between the phenyl ring is 47.5 (1)° and the piperidine ring adopts a chair conformation. In the crystal, mol-ecules are linked by C-H⋯π inter-actions into dimers with the mol-ecules related by twofold symmetry.

2,4-Bis(4-fluoro-phen-yl)-1,5-dimethyl-3-aza-bicyclo-[3.3.1]nonan-9-one.

The asymmetric unit of the title compound, C22H23F2NO, contains two independent mol-ecules, A and B. The bicyclic system adopts a twin-chair conformation in both mol-ecules. The dihedral angles between the fluoro-phenyl rings are 55.27 (8) and 56.37 (7)° in mol-ecules A and B, respectively. The NH groups are not involved in hydrogen bonding due to the steric hindrance of fluoro-phenyl groups. The crystal structure features weak C-H⋯O inter-actions.

2,4-Bis(furan-2-yl)-1,5-dimethyl-3-aza-bicyclo-[3.3.1]nonan-9-one.

In the title compound, C18H21NO3, the bicyclic ring system adopts a twin-chair conformation. The two methyl groups attached to the bicycle are in an equatorial orientation for both rings. One of the furan rings is disordered over two orientations with an occupancy ratio of 0.686 (6):0.314 (6). In the crystal, very long N-H⋯O hydrogen bonds connect the mol-ecules into a chain perpendicular to the ac plane.