Ten different N‐propargyl pyrrole derivatives having various substituents at the C‐2 position were synthesized. These derivatives were converted into indolizine derivatives by the [2+2] cycloaddition reaction of pyrrole N‐allene, forming in situ, by heating in PrOH in basic medium. The structures were characterized by NMR and X‐ray crystallography. The N‐propargylated derivatives smoothly underwent intermolecular cyclizations to produce indolizine derivatives in good yields. We proposed a radical mechanism for the dimerization. Reaction of an allene product with butylated hydroxytoluene (BHT), a radical scavenger, did not give any dimerization product. This result supports the radical reaction.

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