Free / Open‑Source Tools

• IBM RXN for Chemistry

  • Cloud-based platform using transformer neural models for forward and retrosynthesis.

  • Free to use, integrates atom-mapping and reaction prediction workflows.

• ASKCOS (MIT)

  • Automated synthesis planning with reaction prediction and condition recommendation.

  • Open-source, designed for scalable and flexible synthetic route exploration.

• AiZynthFinder

  • Monte Carlo tree search with template-based retrosynthesis.

  • Lightweight, customizable, and easy to integrate into research pipelines.

• DeepRetro

  • Recursive neural networks for multi-step retrosynthesis prediction.

  • GitHub project, adaptable for academic and exploratory research.

• Retrosim / NeuralSym

  • Template-based and neural network retrosynthesis benchmarks.

  • Useful for comparative evaluation of algorithmic performance.

• RXNMapper (IBM)

  • Free atom-mapping tool for reaction mechanism visualization.

  • Often paired with retrosynthesis workflows for accuracy and clarity.

AI-Based Retrosynthesis Tools

Paid / Commercial Tools

• Synthia™ (Merck, formerly Chematica)

  • Expert-curated rules combined with AI for industrial-grade retrosynthesis.

  • Patented strategies widely used in pharma and chemical industries.

• ChemAIRS®

  • Provides diverse synthetic strategies with impurity prediction.

  • Optimizes process chemistry for industrial applications.

• Spaya (Iktos)

  • AI-driven retrosynthesis with synthetic accessibility scoring.

  • Tailored for drug discovery, balancing feasibility and innovation.

• PostEra Manifold

  • Integrates retrosynthesis with medicinal chemistry design.

  • Used in collaborative pharma projects for rapid candidate development.

• ChemAI

  • Generates multiple synthetic routes with mechanism visualization.

  • Suggests reagents/catalysts, enhancing decision-making in synthesis planning.