Some of the important reactions in Organic chemistry for JEE MAINS:

1. Sandmeyer Reaction

2. Gattermann Reaction

3. Balz-Schiemann Reaction

4. Finkelstein Reaction

5. Wurtz Reaction

6. Swartz Reaction

7. Fitting Reaction

8. Wurtz – Fittig Reaction

9. Kolbe’s Reaction

10. Reimer- Tiemann Reaction

11. Gattermann – Koch Reaction

12. Clemmensen Reduction

13. Wolff – Kishner Reduction

14. Haloform Reaction (Iodoform Reaction)

15. Aldol Condensation

16. Cannizzaro Reaction

17. Friedel – Crafts Reaction

18. Grignard Synthesis

19. Esterification Reaction or Fischer Esterification

20. Williamson Synthesis

21. Diazotisation Reaction

I hope my answer helps. All the very best for your future endeavors!