Competing Isomerizations: A Combined Experimental/Theoretical Study of Phenylpentenone Isomerism
Bibliographic record
Abstract
The possible competition of Z/E versus hydrogen-shift isomerization in (E)-5-phenyl-3-penten-2-one (E-1) and (E)-5-phenyl-4-penten-2-one (E-2) was studied, both experimentally and theoretically. Iodine-catalyzed isomerization experiments and computational modeling studies show that the equilibrated system consists predominantly of E-1 and E-2, with E-2 in moderate excess, and with no detectable amounts of the Z (cis) diastereoisomers. Density functional theory (DFT) calculations corroborated the free energy difference (Delta(r) and Delta(r) were -0.7 and -1.1 kcal mol(-1), respectively), and computations of Boltzmann-weighted (1)H NMR spectra were found to be useful in confirming the assignment of the isomers. The relevance of this equilibrium to earlier work on double-bond stabilization is discussed.
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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) | 0.001 | 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) | 0.000 | 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".