Enantioselective oxa‐Diels–Alder Sequences of Dendralenes
Bibliographic record
Abstract
Abstract Diene‐transmissive hetero‐Diels–Alder sequences involving carbonyl dienophiles are reported for the first time. High enantioselectivities are achieved in the reaction of phenylglyoxal with a broad range of dendralene structures, through the optimization of a Pd2+ catalyst system. The initial catalyst‐controlled enantioselective oxa‐Diels–Alder (ODA) cycloaddition to a [3]dendralene generates a dihydropyran carrying a semicyclic diene. This participates in a subsequent catalyst or substrate‐controlled Diels–Alder reaction to generate sp3‐rich fused polycyclic systems containing both heterocycles and carbocycles. Computational investigations reveal a concerted asynchronous mechanism. π‐Complexation of a diene C=C bond to Pd2+ occurs in both the pre‐transition state (TS) complex and in cycloaddition TSs, controlling stereoselectivity. A formal enantioselective [4+2]cycloaddition of a CO2 dienophile is demonstrated.
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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) | 0.001 | 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) | 0.002 | 0.001 |
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".