Synthesizability

Synthesizability refers to the practicality of constructing a chemical compound or material from available starting materials and standard laboratory methods. It encompasses considerations of feasibility, safety, cost, and scalability within current scientific capabilities and regulatory environments. Synthesizability is not a measure of a molecule’s existence or its theoretical appeal, but of how readily a synthesis can be implemented in practice.

Several factors influence synthesizability. The number of synthetic steps, average and overall yields, and the structural complexity of the target affect practicality. The availability and cost of starting materials and reagents, the need for specialized catalysts or equipment, and the required reaction conditions (such as extreme temperatures or controlled atmospheres) also matter. Safety, hazard potential, environmental impact, waste handling, and regulatory constraints are important considerations, as are the feasibility of purification, isolation, and scale-up to larger production.

Assessment methods combine qualitative and quantitative approaches. Cheminformatics develops synthetic accessibility scores and other complexity metrics to compare candidates. Retrosynthetic analysis and computer-aided synthesis planning propose plausible, executable routes. Expert chemists provide judgment on route viability, sometimes supported by pilot-scale experiments or small-batch syntheses.

Applications of synthesizability assessments include guiding library design in drug discovery and materials science, prioritizing molecules for synthesis, and informing process development. Challenges remain, such as the imperfect accuracy of predictive models, data biases, and the balance between pursuing novel structures and maintaining feasible, safe, and scalable routes as synthetic technology evolves.