Base Promoted Three‐component Reaction for Efficient Construction of Spiro[indoline‐3,3′‐quinoline]‐2,5′‐dione.

A convenient synthetic protocol for the construction of spiro[indoline‐3,3′‐quinoline]‐2,5′‐dione motifs was successfully developed by base promoted one‐pot three‐component reaction. In the presence of piperidine, three‐component reaction of ammonium acetate, aromatic aldehydes and the in situ generated 3‐isatyl 1,4‐dicarbonyl compounds, which were derived from base mediated addition of dimedone to 3‐methyleneoxindoles, resulted in two diastereoisomers of spiro[indoline‐3,3′‐quinoline]‐2,5′‐dione derivatives in good yields and with good diastereoselectivity. The stereochemistry of the reaction was clearly elucidated by isolation of two diastereomers and determination of several single crystal structures. [ABSTRACT FROM AUTHOR]