A Mechanistic Study of the Stereochemical Outcomes of Rhodium‐Catalysed Styrene Aziridinations
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract The stereoselective, rhodium‐catalysed aziridination of styrene derivatives with a chiral N ‐mesyloxycarbamate was found to be highly substrate dependent. A density functional theory (DFT) study is herein reported to elucidate the stereochemical outcome of the aziridination process. Rhodium acetate was initially used as a model catalyst, followed by computational studies conducted with Rh 2 [( S )‐nttl] 4 . Both singlet and triplet rhodium nitrene species were identified as intermediates affording concomitant concerted and radical pathways. In the latter case, the radical intermediate appears to undergo a direct ring closure via a minimum energy crossing point (MECP) between the triplet and closed‐shell singlet surfaces. Exceptionally for the m ‐Br‐styrene aziridination, an alternative radical pathway with a carbon‐carbon bond rotation was observed, accounting for the observed 74:26 mixture of diastereomers. The computational analysis also suggests little control of the metal nitrene conformation with Rh 2 (OAc) 4 with the chiral N ‐mesyloxycarbamate: two conformers were located affording two diastereomers of the aziridine and correlating our experimental results. On the other hand, only one conformer was found for the nitrene generated from the chiral N ‐mesyloxycarbamate and Rh 2 [( S )‐nttl] 4 . The so‐called “all‐up” conformer of Rh 2 [( S )‐nttl] 4 was not only the most stable metal nitrene species, but also afforded the lowest energy transition state. The calculated dr for p ‐Br‐styrene aziridination agrees with the observed experimental result. The combination of experimental and computational results offers a detailed mechanistic picture, providing insights for further catalyst development to enhance reactivity and selectivity. magnified image
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.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.001 | 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