Enantiomerically pure decalinic structures from carbohydrates using intramolecular Diels-Alder and Ferrier carbocyclization
Bibliographic record
Abstract
The synthesis of enantiomerically pure decalinic structures, advanced intermediates for the synthesis of the hexahydronaphtalen part of mevinic acids, is described. The key steps are the intramolecular Diels-Alder cycloaddition of a suitably substituted sugar enone obtained via the Ferrier rearrangement of tri-O-acetyl-D-glucal with the appropriate alcohol representing the diene part of the system. Chemical manipulation of the resulting, diastereomerically pure, cycloadduct led to a 5,6-unsaturated carbohydrate which was submitted to the Ferrier carbocylization. This reaction proved difficult likely because of the embedding of the aglycon in a cycle, the hydration product of the double bond being the main product. This compound was in turn transformed into the decalinic structures by treatment in basic medium. The inverse strategy, Ferrier carbocyclization followed by IMDA of an enone and a diene linked via an ester bond was unsuccessful.Key words: Intramolecular Diels-Alder reaction, enantiomerically pure decalin, Ferrier carbocyclization, carbohydrates.
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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) | 0.009 | 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".