Synthesis of novel indolizine derivatives

The reaction of a number of γ‐butyrolactones with azole anions is shown to give γ‐substituted butanoic acids in moderate to good yields. The pyrrolyl and indolylbutanoic acids obtained underwent cyclization in a simple one‐pot procedure employing ethyl chloroformate and boron trifluoride etherate. Some aspects of the chemistry of the resulting indolizin‐8‐ones are described.