Updated May 16, 2026
Retrosynthesis search
Configure step count, precedent, starting material, deep search, and stock.
Retrosynthesis performs a full retrosynthesis search with configurable parameters. Open the Retrosynthesis page from the sidebar to start a new job.
Parameters
| Parameter | Values | Description |
|---|---|---|
| Steps | 2–8 | Number of retrosynthesis steps to search for. |
| Precedent | Well-Precedented → Novel | How closely routes follow training data. |
| Starting material | Optional SMILES | Constrains the search to routes that begin from this molecule. |
| Deep search | On / Off | Enable for complex molecules with ring systems. |
| Commercial stock | Off / Vendors | Filter results to use commercially available starting materials. |
When to tune each
- Higher step count opens up more possibilities but increases compute time. Start at 3 for small molecules, 5 for mid-size drug candidates.
- "Well-Precedented" is conservative — routes look like published chemistry. "Novel" surfaces creative disconnections; good for IP diversity and natural products but needs more chemist judgment.
- Deep search helps with macrocycles, fused polycycles, and natural-product scaffolds. Off by default because it's slower.
- Commercial stock shines in process chemistry; combine with starting-material constraints to find routes from reagents you can actually procure.
What to read next
- Submitting your first retrosynthesis — walkthrough of the submission form.
- Commercial stock filtering — how vendor filtering actually works.
- Troubleshooting — what to do when a job returns empty or is rejected.