Crystal structure of methyl 7-phenyl-6a,7,7a,8,9,10-hexa­hydro-6H,11aH-thio­chromeno[3,4-b]pyrrolizine-6a-­carbox­ylate

In the title compound, C(22)H(23)NO(2)S, the inner pyrrolidine ring (A) adopts an envelope conformation with the methine C atom opposite the fused C—N bond as the flap. The thio­pyran ring (C) has a half-chair conformation and its mean plane is inclined to the fused benzene ring by 1.74 (11)°, and by 60.52 (11)° to the mean plane of pyrrolidine ring A. In the outer pyrrolidine ring (B), the C atom opposite the fused C—N bond is disordered [site-occupancy ratio = 0.427 (13):0.573 (13)] and both rings have envelope conformations, with the disordered C atom as the flap. The planes of the phenyl ring and the benzene ring of the thio­chromane unit are inclined to one another by 65.52 (14)°. In the crystal, mol­ecules are linked by a pair of C—H⋯O hydrogen bonds forming inversion dimers.