Synthesis of Optically Pure (+)‐Puraquinonic Acid and Assignment of Absolute Configuration to Natural (‐)‐Puraquinonic Acid. Use of Radical Cyclization for Asymmetric Generation of a Quaternary Center.
Bibliographic record
Abstract
An asymmetric aldol reaction between aldehyde <b>31</b> and imide <b>32</b>, followed at a later stage by ring-closing metathesis (<b>38</b> → <b>40</b>), are key reactions used to make optically pure allylic alcohol <b>40</b>. Radical\ncyclization of the derived Stork bromo acetals gives lactol ethers <b>43</b>, which were degraded to generate\na quaternary center carrying a methoxycarboxyl group (<b>44</b> → <b>47</b>). Compound <b>47</b> was converted\ninto (+)-puraquinonic acid; and comparison with a natural sample established that the configuration\nof the natural compound is 2<i>R</i> (<b>1</b>).
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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 | 0.002 |
| 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".