Computer-aided synthesis planning
RetroSynthesis is a free retrosynthesis planner for exploring possible ways to make an organic molecule. Draw a structure or enter a SMILES string to search for candidate disconnections and build step-by-step routes toward simpler starting materials.
The planner uses a Monte Carlo tree search guided by a learned reaction policy, reaction templates derived from USPTO literature data, and reaction filters. It expands promising retrosynthetic steps and checks route leaves against ZINC starting-material stock data.
Use the structure editor to draw a target, paste a SMILES string, or try an example molecule. Review proposed routes, reaction steps, and stock matches, then adjust the search settings to explore alternatives.