Mirroring Enzymes: The Role of Hydrogen Bonding in an Asymmetric Organocatalyzed Aza-Henry Reaction—a DFT Study
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Bibliographic record
Abstract
The mechanism of the HQuin-BAM ( 1 ) catalyzed aza-Henry reaction between nitromethane and N -Boc-phenylaldimine was studied using density functional theory (DFT). Deprotonation of nitromethane by the catalyst was revealed to be the rate-limiting step, and C···C bond formation was found to be enantio-determining. The catalyst, in addition to acting as a Brønsted base, served to simultaneously activate both the electrophile and the nucleophile through hydrogen bonding during C···C bond formation and is thus essential for both reaction rate and selectivity. Analysis of the hydrogen bonding interactions revealed that there was a strong preference for the formation of a homonuclear positive-charge-assisted hydrogen bond (homonuclear (+)CAHB), which in turn governed the relative orientation of substrate binding. Furthermore, a direct correlation between the dihedral angle (θ NCCN ) of the reacting substrates and facial selectivity was found. This relationship between θ and facial selectivity was found to be a consequence of optimal secondary interactions and orbital overlap.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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