Grinding of various electron-deficient dienophiles with diverse dienes in a pestle
and mortar for 1–15 minutes afforded the corresponding Diels–Alder adducts in quantitative
yields under catalyst-free and solvent-free conditions, without the necessity for
any purification steps.
Key words
solvent-free reaction - Diels–Alder reaction - cycloaddition - polycyclic compounds
- green chemistry