ChemInform Abstract: 1,3‐Dipolar Cycloadditions of Azomethine Ylides with Dipolarophiles. Part 2. Synthesis of Pyrrolizidines.

Abstract

ChemInform Abstract Proline (I) reacts with the aldehydes (III) to generate azomethine ylides which are trapped by cycloaddition with dimethyl fumarate (II) or maleate (VII) to give mixtures of the pyrrolizidines (IV) -(VI) or (IV), (V), (VIII), and (IX). Azetidine-2-carboxylic acid (X) reacts with (IIIc) and the fumarate (II) to yield the fused pyrrolidine (XI) or oxazolidine (XII). Analogous treatment of (X) with (II) and the aldehyde (IIId) forms the fused pyrrolidines (XIII) and (XIV). Further examples are given in the original paper.