Enantioselective de Novo Synthesis of 4-Deoxy-<scp>d</scp>-hexopyranoses via Hetero-Diels–Alder Cycloadditions: Total Synthesis of Ezoaminuroic Acid and Neosidomycin
Bibliographic record
Abstract
The de novo synthesis of carbohydrates constitutes an important aspect of organic chemistry, and its application toward deoxy sugars is particularly noteworthy in targeting biologically active compounds. The enantioselective preparation of 4-deoxy-D-ribo-, 4-deoxy-D-lyxo-, and 4-deoxy-D-xylo-hexopyranosides, along with their uronate counterparts has been successfully accomplished using hetero-Diels-Alder reactions as the key step. Jacobsen chromium(III) catalyst and a titanium-binaphthol complex have been used to successfully catalyze diene and aldehyde cycloadditions, leading to optically active dihydropyran templates. 6-Hydroxydesosamine, orthogonally protected ezoaminuroic acid, and neosidomycin were synthesized using a comparative study. Also, a novel chiron approach to 4-deoxy-lyxo-hexopyranosiduronic acid methyl ester derivatives was efficiently accomplished starting from readily accessible starting materials. This work represents a systematic and comprehensive study toward a de novo synthesis of 4-deoxy-hexopyranoses via enantioselective hetero-Diels-Alder reactions.
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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) | 0.000 | 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) | 0.001 | 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".