Betaine formation from the reactions of <i>N</i>-heterocyclic carbenes with polarized alkenes
Bibliographic record
Abstract
N-Heterocyclic carbenes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene 1a (IMes) or 1,3-bis(2,6-di-iso-propylphenyl)imidazolidene 1b (SIPr)] react with the polarized alkenes 2 and 4 to form the crystalline betaines 3a, 3b, and 5a. Furthermore, a one-pot reaction between an aldehyde, malononitrile, and an imidazolium salt of an N-heterocyclic carbene has been developed for the efficient preparation of betaine 5a without isolation of the free carbene. Full characterization data, including X-ray crystal structures, is reported for the three synthesized betaines. The structures of the betaines 3a, 3b, and 5a shed new light on the initial products formed in the reactions between N-heterocyclic carbenes and compounds containing polarized double bonds.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.000 |
| 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) | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), 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".