Reactivity of the Chiral Metallic Brønsted Acid [(η<sup>6</sup>-<i>p</i>-MeC<sub>6</sub>H<sub>4</sub><i>i</i>Pr)Ru(κ<sup>3</sup><i>P</i>,<i>O,O</i>′-<b>POH</b>)][SbF<sub>6</sub>]<sub>2</sub>(<b>POH</b>= (<i>S</i><sub>C1</sub>,<i>R</i><sub>C2</sub>)-Ph<sub>2</sub>PC(Ph)HC(OH)HCH<sub>2</sub>OMe) toward Aldimines
Bibliographic record
Abstract
Dichloromethane solutions of complex 1 catalyze both the aza-Diels–Alder (ADA) reaction of aldimines with cyclopentadiene and the aza-Friedel–Crafts (AFC) reaction between aldimines and indoles. Racemic adducts were obtained in both cases. NMR measurements of mixtures of the aldimine N -(4-methylbenzylidene)aniline ( I ) and 1, in a 20/1 molar ratio, reveal the formation of the deprotonated compound 2 and the corresponding iminium cation HI + (H–N + ). This cation is responsible for the achiral catalysis. Below 273 K, in 1/1 molar ratio mixtures of 1 and I, the chiral species 1·I (O–H···N) and 2·HI + (O – ···H–N + ) were formed by intermolecular hydrogen bonding and proton transfer, respectively. The latter solutions catalyze stoichiometrically the ADA reaction between aldimine I and HCp with 16% ee. With 5 mol % of catalyst loading, a 6% ee can be obtained if the aldimine is slowly added to the solution (20 equiv in 60 h). Above 273 K, solutions containing 1 and aldimine I irreversibly evolve to the aniline complex 3, which was isolated as a racemic mixture. The molecular structure of 3 has been determined by X-ray diffractometric methods. Hydride 5, an intermediate in this reaction, has been isolated and spectroscopically characterized. On the basis of synthetic and spectroscopic studies, a plausible pathway for the formation of 3 from 1 is proposed.
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How this classification was reachedexpand
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 | 0.014 | 0.011 |
| Meta-epidemiology (narrow) | 0.020 | 0.021 |
| Meta-epidemiology (broad) | 0.021 | 0.018 |
| Bibliometrics | 0.010 | 0.036 |
| Science and technology studies | 0.008 | 0.010 |
| Scholarly communication | 0.005 | 0.010 |
| Open science | 0.018 | 0.012 |
| Research integrity | 0.014 | 0.018 |
| Insufficient payload (model declined to judge) | 0.001 | 0.010 |
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; both teacher heads agree on what is shown here.
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".