Hey as per your demand here I am providing you details of Important Reactions in Organic Chemistry for IIT JEE

Here I am giving you list of Important Reactions in Organic Chemistry for IIT JEE
Aldol condensation
Balz Schiemann Reaction
Benzoin Condensation
Cannizaro reaction
Carbylamine reaction
Claisen Condensation
Cross Aldol Condensation
Friedel - Crafts Reaction
Fries rearrangement
Garbriel phthalamide synthesis
Hell_Volhard_Zelinsky Halogenation
Hofmann Bromamide Reaction
Kolbe Schmitt Reaction
Reimer Tiemann Reaction
Rosenmund reduction
Sandmeyer Reaction
Schotten Baumann Reaction
SN 2 Reaction
SN1 Reaction
Wolf Kishner Reaction

Here I am giving you Tips to Crack these Reactions:

More and more practice because practice makes a student perfect.
If we remember the reaction by name, then it is more helpful because sometimes questions are directly asked by the reactions names.
Never get frightened by the lengthy mechanisms of the reactions.
Try to understand the mechanism instead of mugging it because questions asked in JEE will be totally new and only concepts will help there.