Observation of a Tricyclic[4.1.0.0<sup>2,4</sup>]heptane During a Michael Addition-Ring Closure Reaction and a Computational Study on Its Mechanism of Formation
Bibliographic record
Abstract
]heptane, that is formed during a Johnson-Corey-Chaykovsky reaction on a cyclopentenone. Two (of four possible) bicyclic products are selectively formed by addition of a COOEt-stabilized sulfur ylide onto the Michael acceptor. The tricyclic product is formed subsequently via a retro Michael elimination of a hindered ether followed by addition of a further cyclopropyl moiety, affecting only one of the two bicyclic products initially formed. The experimental reaction outcome was rationalized using density functional theory (DFT), investigating the different Michael-addition approaches of the sulfur ylide, the transition state (TS) energies for the formation of possible zwitterionic intermediates and subsequent reactions that give rise to cyclopropanation. Selective formation of only two of the four possible products occurs due to the epimerization of unreactive intermediates from the other two pathways, as revealed by energy barrier calculations. The formation of the tricyclic product was rationalized by evaluation of energy barriers for proton abstraction required to form the intermediate undergoing the second cyclopropanation. The selectivity-guiding factors discussed for the single and double cyclopropanation of this functionalized Michael-acceptor will be useful guidelines for the synthesis of future singly and doubly cyclopropanated compounds.
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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 | 0.000 |
| 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".