A highly efficient protocol for the regio- and stereo-selective synthesis of spiro pyrrolidine and pyrrolizidine derivatives by multicomponent reaction

A series of novel spiro[acenaphthylene-1,2′-pyrrolidine] (4), spiro[acenaphthylene-1,2′-pyrrolizidine] (7), and spiro[indoline-3,2′-pyrrolidine] derivatives (9) containing cyano group were successfully synthesized via a three-component 1,3-dipolar cycloaddition reaction of acenaphthenequinone or isatin, sarcosine or proline, and Knoevenagel adducts in refluxing aqueous methanol. In this intermolecular three-component combinatorial process it is amazing that three stereogenic centers with one spiro carbon are controlled very well. The structure and relative stereo-chemistry of cycloadducts were carried out by single crystal X-ray diffraction, as well as by the help of 1H, 13C, and HMBC spectroscopy.