Silver-catalyzed spirolactonization: first synthesis of spiroisoindole-γ-methylene-γ-butyrolactones

γ-Acetylenic carboxylic acids are cyclized to spirolactones under mild conditions, in the presence of Ag2CO3 catalyst. The corresponding spiro-5-alkylidene-γ-butyrolactones were isolated in high yields, and this process constitutes an easy and efficient route to analogous structures of natural products of biological interest.

Spirolactonization of isoindoloacetylenic carboxylic acids was efficiently catalyzed by silver carbonate under extremely mild conditions. This process was found to be an easy route to novel spiro-γ-methylene-γ-butyrolactones.Figure optionsDownload as PowerPoint slide