DBU-promoted 3+2 cycloaddition for the synthesis of trispiro heterocycles from acetylpyrazolyl-substituted oxindoles and substituted isatins

Key Points

• This reaction produces polyspiro oxindole-γ-butyrolactones, enhancing synthetic accessibility.
• The reaction exhibits high scalability and broad substrate scope, matching various substitutions.
• DBU-induced annulation offers a mild reaction environment, making it safer and more versatile.
• The findings may enable further exploration of spiro compounds in medicinal chemistry.