Design of a chiral molecular pocket in a Ni(II) complex to improve stereoselectivity in the kinetic resolution of racemic epoxides with CO2
Bibliographic record
Abstract
The kinetic resolution of racemic epoxides using the carbon dioxide (CO 2 ) molecule is of significant practical interest because the reaction yields the valuable products – enantiomerically enriched cyclic carbonates (1,3-dioxolan-2-ones), along with the remaining opposite enantiomer of the epoxide. However, one is the main challenges in this direction is the absence of the universal and efficient chiral catalytic systems for the resolution of different epoxides by CO 2 with a high selectivity factor ( s ). In this context, we herein present a perspective proof-of-concept approach for the improvement of stereoselectivity in the resolution of terminal epoxides by a rational design of an appropriate chiral molecular pocket in a Ni(II) complex based on commercially available ( S )-(2-aminomethyl)pyrrolidine and 3,5-di- tert -butylsalicylaldehyde. The obtained chiral Ni(II) complex with iodide-anion catalyzes the kinetic resolution of epoxides by CO 2 with s -factor up to 7.8, while the addition of a suitable chiral ligand to this system, particularly, ( S )-(2-anilinomethyl)pyrrolidine led to the increasing of s -factor up to 11.5 in the case of challenging styrene oxide ( ee of styrene cyclic carbonate was 82%) which is being one of the best results for this substrate to date. It is gratifying to note that even achiral co-ligands can be used, greatly simplifying the catalytic system. The experimental and spectral data and DFT calculations revealed the mechanism of catalysis and enantioselection.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".