Synthesis of spiropyrrolidines: 1,3‐dipolar cycloaddition reactions of an azomethine ylide to unusual dipolarophiles; a molecular orbital study of the cycloaddition reaction

Abstract

A simple and efficient method for the synthesis of novel spiropyrrolidines has been accomplished by regioselective 1,3-dipolar cycloaddition reactions of an azomethine ylide generated by thermal-ring opening of cis-1-cyclohexyl-2-phenyl-3-benzoyl aziridine with various (E)-3-arylidene-4-chromanones. The synthesis proceeds in good yield to afford novel spiropyrrolidines, 1-cyclohexyl-2-phenyl-3-aryl-5-benzoylpyrrolidine-spiro-[4.3′]4′-chromanones. The X-ray crystal structure analysis of one of the products confirms its structure. Molecular orbital calculations were performed to investigate the regioselectivity of the cycloaddition process. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 500–507, 1999