Underexplored Catalysts as General Structures: Application of Machine Learning Techniques for Reaction-Specific Datasets
Bibliographic record
Abstract
General catalysts are usually identified through broad experimental screening to find structures that perform reliably across many substrates and reaction classes. In secondary amine organocatalysis, historical reporting is strongly skewed toward a small set of standard catalysts, leaving many plausible scaffolds underexplored and difficult to evaluate objectively. Here, we apply a bias-aware machine learning workflow designed for small, uneven datasets to prioritize candidate general catalysts from limited historical data. Within the iminium-based reaction space used to construct the curated and virtually balanced dataset, this analysis surfaced several high-performing candidates, including a rarely studied imidazolidinone bearing a benzyl-protected indole substituent. Despite minimal precedent, this scaffold performed competitively in experimental benchmarking and external transferability tests. In a retrospective analysis restricted to pre-2005 examples, the same workflow prioritized catalyst families that later became widely adopted (e.g., diarylprolinol silyl ethers and imidazolidinones) among its top candidates, consistent with earlier prioritization from the literature available at the time. Together, these results show how bias-aware modeling can highlight overlooked scaffolds and reduce the experimental burden required to identify broadly useful catalysts. Pairing targeted experiments with data-driven prioritization provides a practical route to expanding the set of reliable secondary-amine catalysts beyond the structures that dominate current practice.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.017 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".