Lewis Acid Catalyzed Unprecedented [3 + 2] Cycloaddition Yields 3,3′-Pyrrolidinyldispirooxindoles Containing Four Contiguous Chiral Stereocenters with Two Contiguous Quaternary Spirostereocenters

A Lewis acid catalyzed domino reaction cascades through azide–alkene cycloaddition, rearrangement, aziridine ring opening, and azomethine cycloaddition with a parent dipolarophile, resulting in 3,3′-pyrrolidinyldispirooxindoles containing four contiguous chiral stereocenters with two contiguous quaternary spirostereocenters

N-tert-Butyl-2-(2,6-dichlorophenyl)imidazo[1,2-a]pyrazin-3-amine

In the title compound, C16H16Cl2N4, the imidazole ring mean plane makes a dihedral angle of 70.01 (1)° with the phenyl ring. The Cl atoms deviate by −0.0472 (6) and 0.0245 (8) Å from the plane of their attached benzene ring. In the crystal, molecules are linked via pairs of C—H...N hydrogen bonds, forming inversion dimers

N-tert-Butyl-2-[4-(dimethylamino)phenyl]imidazo[1,2-a]pyrazin-3-amine

In the title compound, C18H23N5, the imidazole ring makes a dihedral angles of 3.96 (8) and 19.02 (8)°, respectively, with the pyrazine and benzene rings while the dihedral angle between the pyrazine and benzene rings is 16.96 (7)°. In the crystal, molecules are linked via N—H...N hydrogen bonds, forming chains along [010]. These chains are linked by C—H...N hydrogen bonds, forming two-dimensional networks lying parallel to (001)