The role of molecular geometry in the Wolff rearrangement of α-diazocarbonyl compounds Conformational control or structural constraints?
Bibliographic record
Abstract
Relaxed scans of potential energy surfaces for the loss of nitrogen from four different diazocarbonyl compounds: 3-diazo-2-butanone (1), 2-diazocyclohexanone (2), methyl diazomalonate (3), and diazo Meldrum's acid (4), were conducted at the B3LYP/6-31+G(d,p) level. The geometries of species and transition states involved in the process were optimized at the B3LYP/6-311+G(3df,2p) level, while electronic energies were computed using the MP2(full)/aug-cc-pVTZ method. These calculations suggest that the rigidity of cyclic molecules, rather than the conformational structure of the starting diazocarbonyl compounds, defines the pathway of the dediazotization reaction. In acyclic diazocarbonyl compounds, loss of nitrogen results in the formation of a carbene, which is stabilized by the overlap of the system of carbonyl group and the unshared electron pair of a singlet carbene. On the contrary, in small- to medium-sized cyclic systems, carbonyl carbenes are unable to attain a stabilizing orthogonal conformation. Consequently, cyclic carbonyl carbenes are less stable, and the concerted Wolff rearrangement becomes the predominant process. Transition states for the concerted Wolff rearrangement and for the formation of carbonyl carbenes have a very similar geometry.Key words: diazocarbonyl compounds, Wolff rearrangement, conformation, carbene, ketene.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".