Retrosynth
Plan a synthesis in reverse: disconnect the target molecule one valid step at a time until you arrive at something you already have on the shelf.
How to play
You hold the target molecule and work backward. Each retro step is a disconnection that must be chemically valid, sometimes needing the right mechanism partner. Keep peeling until the molecule you're holding is a starting material on the shelf.
- Pick a retro-disconnection from the offered options to break a bond or transform a group.
- Supply the correct mechanism partner when a step prompts for one.
- Each valid step appends to your route; an invalid one is rejected.
- Land on a shelf starting material to complete the synthesis — scored on steps against par.
Controls
- Desktop: click an option to take a retro step, click a partner when prompted, and use Hint if stuck; choose Daily/Practice and a difficulty.
- Phone & tablet: tap options and partners — fully touch-friendly.
Tips & strategy
- Look for the bond that most simplifies the skeleton; the best disconnection usually splits the molecule near the middle.
- Match each functional group to the role it plays before choosing its mechanism partner.
- Fewer steps beats par — avoid disconnections that lead away from anything on the shelf.
What you'll learn
Retrosynth captures the backward-planning logic of retrosynthetic analysis, the organic chemist's craft.
- Skills: organic chemistry, retrosynthesis, backward planning
- Best for: advanced high school / college
- For parents & teachers: retrosynthesis, the organic chemist's logic.
About Retrosynth
Retrosynth captures the backward-planning logic that organic chemists call retrosynthetic analysis, turning it into a tidy step-count puzzle. It's an original, free browser game with three difficulties and daily plus practice modes.
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