Diastereoselective Synthesis of Alkylated 1,4-Cyclohexadiene Esters Using Epimeric Pyrroloimidazolones
Bibliographic record
Abstract
A pair of ortho-benzoate esters containing epimeric pyrroloimidazolones undergo sequential Birch reduction and diastereoselective alkylation to provide products ranging from 88:12 to >95:5 diastereomeric ratio (dr) for the syn-epimer, and 50:50 to 95:5 dr for the anti-epimer. The stereochemistry of the products is confirmed by a combination of X-ray crystallography on a key anti-epimer-derived product, in combination with specific rotation measurements of enantiomers that are prepared from the syn or anti starting materials. A diastereomerically pure allyl-substituted substrate is shown to undergo Cope rearrangement, which transposes the quaternary chiral center to a remote position without racemization. This work is complementary to asymmetric reductive alkylation reported previously by Schultz using anisole substrates with chiral benzamide auxiliaries in that the pyrroloimidazolones act as surrogates for the methoxy group.
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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) | 0.003 | 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".