The Mechanism and Origin of Enantioselectivity in the Rhodium-Catalyzed Asymmetric Ring-Opening Reactions of Oxabicyclic Alkenes with Organoboronic Acids: A DFT Investigation
Bibliographic record
Abstract
The mechanism and origins of enantio- and stereoselectivity in the asymmetric ring-opening (ARO) reactions of oxabicyclic alkenes with organoboronic acids catalyzed by rhodium/Josiphos has been examined at the B3LYP/defTZVP level of theory. The mechanism consists of four steps including transmetalation, carborhodation, β-oxygen elimination, and hydrolysis. Energetic discrimination in the chirality-imparting step arises from attractive C–H−π interactions between the transmetalated aryl group and the Josiphos ligand, as well as steric clashes between the Josiphos ligand and the oxabicyclic alkene. Computational results indicate that the rate-determining step is involved in the hydrolysis of the rhodium(I) alkoxide from the ring-opened intermediate. In the overall catalytic cycle, the greatest free energy barrier is 23.4 kcal/mol, which supports that the Rh-catalyzed ARO reactions take place at mild reaction conditions, which is consistent with experimental observations.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.004 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".