Scalable and Cost-Efficient de Novo Template-Based Molecular Generation
This work addresses three key challenges in template-guided molecular generation: high synthetic cost, difficulty in scaling the building block library, and underutilization of small fragments. We propose a recursive, cost-guided generative framework based on Generative Flow Networks (GFlowNets). Methodologically, we design a backward policy network coupled with an auxiliary synthetic cost predictor, introduce a dynamic building block library that reuses intermediate molecular states, and employ a penalty mechanism to balance exploration and exploitation. Our key contribution lies in explicitly embedding synthetic cost into the generative process, enabling end-to-end differentiable optimization; the dynamic library mechanism markedly improves both diversity and efficiency—especially with limited building block sets. On standard templated molecular generation benchmarks, our approach generates higher-quality, more diverse molecules at lower synthetic cost, achieving state-of-the-art performance.