Peroxy-Carbenium Mediated Asymmetric Synthesis of 1,2-Dioxanes and 1,2-Dioxolanes
Bibliographic record
Abstract
The endoperoxide scaffold is found in numerous natural products and synthetic substances with pharmaceutical interest. The principal challenge to their synthetic access remains the preparation of chiral compounds, due to the weakness of the peroxide bond, which limits the scope of available or applicable methods. Here, we demonstrate how peroxycarbenium species can be trapped by silylated nucleophiles with high enantioselectivities, and diastereoselectivities when applicable, using a chiral imidophosphorimidate (IDPi) as catalyst. The scope of the methodology is broad, encompassing a large varie-ty of enoxysilanes, and yielding 1,2-dioxanes or 1,2-dioxolanes. Peroxides can be converted into chiral alcohols or trans-epoxides, and the methodology was applied in a key step of the total synthesis of ethyl plakortide Z, enhancing the selectivi-ty compared to conventional a Lewis acid. Kinetic studies demonstrated that tert-butyldimethylsilylated nucleophiles are more potent than trimethylsilylated ones. Furthermore, it was observed that the reaction necessitates an induction period, indicating the formation of a silylium species that behaves as the true catalyst.
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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 | 0.001 |
| 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".