Biocatalytic Synthesis of α,β-Unsaturated 2-Keto Acids and Derivatives Using the Promiscuous Aldolase, NahE
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Bibliographic record
Abstract
Abstract Type I aldolases catalyze carbon–carbon bond-forming reactions to form a diverse set of products in nature but often display high selectivity for their natural substrates. One such aldolase, NahE, is known to catalyze the condensation of pyruvate with a wide range of aldehydes to give trans-4-phenyl-2-oxo-3-butenoic acids under mild aqueous conditions. These α,β-unsaturated 2-oxo acids are versatile intermediates for synthetic transformations. NahE has also been used for the synthesis of α-fluoro-β-hydroxy esters, β-hydroxy esters, and quinaldic acids. However, a thorough study of the substrate scope on a practical scale has not been performed for the native NahE-catalyzed aldol condensation reaction. Here we report that NahE can accept >35 (hetero)aromatic and aliphatic aldehydes. Most condensation products derived from substituted benzaldehydes were isolated in >95% yield without need for further purification, while non-benzaldehyde substrates gave the corresponding products in isolated yields between 26% and 98%. Reactions could be performed on gram scale. These products could be converted into α,β-unsaturated carboxylic acids in up to 93% yield over two steps. This reaction sequence was also performed using whole cells in up to 79% yield. This work demonstrates that NahE is a robust, efficient, and versatile catalyst for organic synthesis.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 it