Molecular rearrangements can simplify a synthesis by creating a difficult bond while reorganizing an existing framework. Selecting the right transformation requires more than matching a substrate class to a named reaction.
Start with the desired bond changes
Map the migrating group, the destination atom, and the functional group required after rearrangement. Then evaluate whether the necessary reactive intermediate is compatible with the rest of the molecule.
Evaluate development constraints
Reagent hazards, temperature range, substrate availability, impurity profile, analytical methods, and scale all affect route choice. A practical strategy balances chemical elegance with controllability and reproducibility.